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[vsnet-grb-info 37303] GRB 250212A: Fermi GBM Final Real-time Localization
by GCN Circulars 12 Feb '25

12 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39294 SUBJECT: GRB 250212A: Fermi GBM Final Real-time Localization DATE: 25/02/12 01:00:30 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply(a)GIOC.nsstc.nasa.gov> The Fermi GBM team reports the detection of a likely LONG GRB At 00:49:53 UT on 12 Feb 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250212A (trigger 761014198.925334 / 250212035). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 282.5, Dec = 52.8 (J2000 degrees, equivalent to J2000 18h 49m, 52d 47'), with a statistical uncertainty of 8.1 degrees. The angle from the Fermi LAT boresight is 127.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250212035/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250212035/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250212035/… View this GCN Circular online at https://gcn.nasa.gov/circulars/39294. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37302] LIGO/Virgo/KAGRA S250206dm: AT 2025bbo observations with WFST
by GCN Circulars 12 Feb '25

12 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39293 SUBJECT: LIGO/Virgo/KAGRA S250206dm: AT 2025bbo observations with WFST DATE: 25/02/12 00:33:45 GMT FROM: Zhengyan Liu at USTC <ustclzy(a)mail.ustc.edu.cn> Z. L. Xu, D. Z. Meng, Z. Y. Liu, J.-A. Jiang, W. Zhao, M. X. Cai, T. G. Wang, X. Kong, Z. G. Dai, L. L. Fan (USTC), Y. Z. Fan, J. J. Geng, Z. P. Jin, X. F. Wu (PMO) report on behalf of the WFST Collaboration: We conducted follow-up observations of gravitational wave event S250206dm (the LIGO-Virgo-Kagra Collaboration, GCN 39175) using the Wide Field Survey Telescope (WFST Collaboration; Wang et al., 2023). Our follow-up observations (Liu et al, GCN 39249) in r and i bands covered the region of AT2025bbo (Smartt et al, GCN 39244). Additionally, after checking WFST archive data, we found that one 60s r-band exposure (a 5-sigma limiting magnitude of 22.02) taken at 2025-01-12T13:57:44 UTC covered the region as well. We performed image subtraction for WFST r-band images from 2025-02-07T14:23:27 UTC using the 2025-01-12 exposure as template, and for WFST i-band images using the first exposure taken at 2025-02-07T13:50:35 UTC as template. After image subtraction, we do not found any residuals in all difference images in two bands, suggesting that AT2025bbo is unlikely a transient occured aftet the GW event S250206dm (also see Chen et al, GCN 39285). View this GCN Circular online at https://gcn.nasa.gov/circulars/39293. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37301] LIGO/Virgo/KAGRA S250211be: Updated Sky localization
by GCN Circulars 11 Feb '25

11 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39292 SUBJECT: LIGO/Virgo/KAGRA S250211be: Updated Sky localization DATE: 25/02/11 23:06:19 GMT FROM: Sylvia Biscoveanu at Northwestern CIERA <sylvia.biscoveanu(a)ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S250211be (GCN Circular 39277). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S250211be For the Bilby.multiorder.fits,0 sky map, the 90% credible region is well fit by an ellipse with an area of 94 deg2 described by the following DS9 region (right ascension, declination, semi-major axis, semi-minor axis, position angle of the semi-minor axis): icrs; ellipse(11h45m, +25d11m, 8.14d, 3.67d, 84.71d) Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3337 +/- 1194 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380 View this GCN Circular online at https://gcn.nasa.gov/circulars/39292. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37300] GRB 250207A: Fermi GBM Observation
by GCN Circulars 11 Feb '25

11 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39291 SUBJECT: GRB 250207A: Fermi GBM Observation DATE: 25/02/11 21:31:46 GMT FROM: oindabimukherjee(a)gmail.com O. Mukherjee (USRA), R. Hamburg (USRA) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team: "At 01:16:03.15 UT on 07 February 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250207A (trigger 760583768/250207053). which was also detected by Swift BAT (Ferro et al. 2025, GCN 39182), COLIBRÍ/DDRAGO (Angulo et al. 2025, GCN 39186), Swift/UVOT (Kuin et al. 2025, GCN 39199), and Konus-Wind (Ridnaia. et al. 2025, GCN 39284) The Fermi GBM Final Real-time Localization (GCN 39181) is consistent with the Swift BAT position. The angle from the Fermi LAT boresight is 46 degrees. The GBM light curve consistes of a single emission episode with multiple peaks with a duration (T90) of about 20 s (50-300 keV). The time-averaged spectrum from T0-3.1 to T0+25.6 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -1.10 +/- 0.06 and the cutoff energy, parameterized as Epeak, is 290 +/- 30 keV. The event fluence (10-1000 keV) in this time interval is (1.04 +/- 0.04)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+12 s in the 10-1000 keV band is 4.7 +/- 0.3 ph/s/cm^2. A Band function fits the spectrum equally well with Epeak= 240 +/- 30 keV, alpha = -1.03 +/- 0.08 and beta = -2.3 +/- 0.3. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog: https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html For Fermi GBM data and info, please visit the official Fermi GBM Support Page: https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/" View this GCN Circular online at https://gcn.nasa.gov/circulars/39291. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37299] GRB 250206A: Fermi GBM Observation
by GCN Circulars 11 Feb '25

11 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39290 SUBJECT: GRB 250206A: Fermi GBM Observation DATE: 25/02/11 20:44:49 GMT FROM: oindabimukherjee(a)gmail.com O. Mukherjee (USRA) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team: "At 19:51:31.93 UT on 06 February 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250206A (trigger 760564296/250206827). which was also detected by Fermi-LAT (Gupta et al. 2025, GCN 39233) and Konus-Wind (Ridnaia et al. 2025, GCN 39283). The Fermi GBM on-ground location is consistent with the Fermi-LAT position. The angle from the Fermi LAT boresight is 33 degrees. The GBM light curve consists of a multipeaked emission episode followed by a single peaked emission episode with a duration (T90) of about 64.3 s (50-300 keV). The time-averaged spectrum from T0-2.0 to T0+79.9 s is best fit by a Band function with Epeak = 187 +/- 8 keV, alpha = -0.73 +/- 0.04, and beta = -2.6 +/- 0.2. The event fluence (10-1000 keV) in this time interval is (2.66 +/- 0.05)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+1.7 s in the 10-1000 keV band is 10.4 +/- 0.3 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog: https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html For Fermi GBM data and info, please visit the official Fermi GBM Support Page: https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/" View this GCN Circular online at https://gcn.nasa.gov/circulars/39290. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37298] GRB 250205A / EP250205A: radio detection with the VLA
by GCN Circulars 11 Feb '25

11 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39289 SUBJECT: GRB 250205A / EP250205A: radio detection with the VLA DATE: 25/02/11 16:51:06 GMT FROM: Stefano Giarratana at INAF-OAB <s.giarratana(a)ira.inaf.it> S. Giarratana (INAF-OAB), M. Giroletti (INAF-IRA), G. Ghirlanda (INAF-OAB), N. Di Lalla (Stanford Univ.), N. Omodei (Stanford Univ.), O. S. Salafia (INAF-OAB) At 08:59:34 UT on 2025 Feb 7 (T_mid = 1.51 days post-burst) the Karl G. Jansky VLA observed the field of GRB 250205A / EP250205A (Saccardi et al., GCN 39154; Mukherjee et al., GCN 39171) in three bands, with central frequencies of 6, 10 and 15 GHz. The standard 3C286 was used as bandpass and flux density calibrator, while J0741+3112 was used as phase calibrator. From a preliminary analysis, an unresolved radio source is detected at a position (J2000): RA: 07:34:02.649 +- 0.003 Dec: 32:22:18.84 +- 0.05 consistent with the X-ray (Kennea et al., GCN39161; Liu et al., GCN 39165) and optical (Gompertz et al., GCN 39156; Palmerio et al., GCN 39159; de Ugarte Postigo et al., GCN 39160; Watson et al., GCN 39162; Busmann et al., GCN 39169) position of the transient. The preliminary analysis yields the following results: ================================================================ T_mid Freq Peak r.m.s. Beam PA [days] [GHz] [uJy/b] [uJy/b] [arcsec^2] [deg] ================================================================ 1.51 6 27 7 0.49x0.32 66 1.51 10 44 8 0.32x0.19 65 1.51 15 40 7 0.19x0.13 66 ================================================================ No source is detected with a >3sigma confidence at the aforementioned position in previous radio surveys (NVSS, FIRST, VLASS), all of which have r.m.s. noise levels above 100 uJy/b. We would like to thank the staff of the VLA for approving, executing, and processing the observations. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. These observations were carried out as part of project SF171028, approved in the framework of the Fermi - NRAO joint program agreement. View this GCN Circular online at https://gcn.nasa.gov/circulars/39289. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37297] IceCube-250207A: One candidate from the Zwicky Transient Facility
by GCN Circulars 11 Feb '25

11 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39288 SUBJECT: IceCube-250207A: One candidate from the Zwicky Transient Facility DATE: 25/02/11 16:35:05 GMT FROM: Jannis Necker at DESY <jannis.necker(a)desy.de> Jannis Necker, Akshay Eranhalodi (DESY), Robert Stein (JSI), Sven Weimann (Ruhr University Bochum), and Anna Franckowiak (Ruhr University Bochum) report: On behalf of the Zwicky Transient Facility (ZTF) and Global Relay of Observatories Watching Transients Happen (GROWTH) collaborations: As part of the ZTF neutrino follow up program (Stein et al. 2023), we observed the localization region of the neutrino event IceCube-250207A (Sommani et. al, GCN 39203) with the Palomar 48-inch telescope, equipped with the 47 square degree ZTF camera (Bellm et al. 2019, Graham et al. 2019). We started observations in the g- and r-band beginning at 2025-02-08 06:52 UTC, approximately 28.7 hours after event time. We covered 98.9% (9.8 sq deg) of the reported localization region. This estimate accounts for chip gaps. Each exposure was 300s with a typical depth of 21.0 mag. The images were processed in real-time through the ZTF reduction and image subtraction pipelines at IPAC to search for potential counterparts (Masci et al. 2019). AMPEL (Nordin et al. 2019, Stein et al. 2021) was used to search the alerts database for candidates. We reject stellar sources (Tachibana and Miller 2018) and moving objects, and apply machine learning algorithms (Mahabal et al. 2019) . We are left with the following high-significance transient candidate by our pipeline, lying within the 90.0% localization of the skymap. +--------------------------------------------------------------------------------+ | ZTF Name | IAU Name | RA (deg) | DEC (deg) | Filter | Mag | MagErr | +--------------------------------------------------------------------------------+ | ZTF25aafgnar | ------- | 131.6422069 | +19.3306551 | r | 20.68 | 0.16 | +--------------------------------------------------------------------------------+ ZTF25aafgnar was first detected on 2025-01-19. The source is somewhat red, with a g-r colour of 0.3. Due to the offset of 0.92 arcsec from the nucleus of its host SDSS J084634.07+191950.9, it appears most likely to be a supernova. Forced photometry reveals ZTF pre-detections beginning on 2025-01-19, demonstrating that the supernova predates the detection of IC250207A. The source reached a peak magnitude of m=20.2 in g-band on 2025-01-23, and has since faded by 0.5 mag. Photometric redshift estimates for the host galaxy from Legacy Survey suggest a distance of z = 0.26 +/- 0.06, with a 95% lower limit of z>0.165, implying a peak absolute magnitude of at least M<-19.4. The colour and implied absolute magnitude are consistent with a supernova origin for this source. The timing of the neutrino detection excludes any choked-jet neutrino production models, but CSM-interaction neutrino production models would still be viable. Spectroscopic observations are planned to determine the nature of this transient. ZTF and GROWTH are worldwide collaborations comprising Caltech, USA; IPAC, USA; WIS, Israel; OKC, Sweden; JSI/UMd, USA; DESY, Germany; TANGO, Taiwan; UW Milwaukee, USA; LANL, USA; TCD, Ireland; IN2P3, France. GROWTH acknowledges generous support of the NSF under PIRE Grant No 1545949. Alert distribution service provided by DIRAC@UW (Patterson et al. 2019). Alert database searches are done by AMPEL (Nordin et al. 2019). Alert filtering is performed with the nuztf (Stein et al. 2021, https://github.com/desy-multimessenger/nuztf ). View this GCN Circular online at https://gcn.nasa.gov/circulars/39288. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37296] EP250207b: Tentative z-band brightening source
by GCN Circulars 11 Feb '25

11 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39287 SUBJECT: EP250207b: Tentative z-band brightening source DATE: 25/02/11 16:01:30 GMT FROM: Andrew Levan at Radboud University <a.levan(a)astro.ru.nl> Morgan Fraser (UCD), Andrew J. Levan (Radboud), Daniele B. Malesani (DAWN/NBI and Radboud), Peter G. Jonker (Radboud), Jonathan A. Quirola-Vásquez (Radboud), Javi Sánchez-Sierras (Radboud), Franz E. Bauer (PUC), Antonio Martin-Carrillo (UCD), report on behalf of a larger collaboration: We report on Gemini North + GMOS observations of the localisation region of the fast X-ray transient EP250207b (Zhou et al., GCN 39266). 6x60 s images were taken in z-band on 2025 Feb. 10 (MJD 60716.44; Malesani et al., GCN 39270) and 5x60 s on Feb. 11 (MJD 60717.48). Performing image subtraction between the two average z-band images, we see a marginal transient in the difference image that has brightened between the two epochs, located at coordinates: RA(J2000) = 11:10:02.8 Dec(J2000) = -07:52:05.8. A source is present at the transient location in both z-band epochs as well as in the Legacy survey. Aperture photometry of the object in the two epochs is consistent with a modest brightening by 0.25 +/- 0.10 mag between the two epochs. The position of the source is offset by about 6.5" to the north of the WISEA J111002.65-075211.9 nucleus, the z=0.082 galaxy that lies within the error circle of EP250207b (Malesani et al., GCN 39270; Levan et al., GCN 39278). If the brightening of this source is real, the association with WISEA J111002.65-075211.9 becomes less clear, and the distance of this event would remain undetermined. We do not see any evidence for transient emission in z-band at the location of the source identified by Eyles-Ferris et al. (GCN 39281) in our subtractions, but we note that the central regions of WISEA J111002.65-075211.9 are subject to substantial uncertainties due to subtraction residuals. Further observations of this field are planned to establish the reality of this object. We thank the staff of Gemini for their excellent support in securing these observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/39287. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37295] LIGO/Virgo/KAGRA S250206dm: continued in SOAR galaxy targeted observations and identification of one possible transient
by GCN Circulars 11 Feb '25

11 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39286 SUBJECT: LIGO/Virgo/KAGRA S250206dm: continued in SOAR galaxy targeted observations and identification of one possible transient DATE: 25/02/11 15:01:05 GMT FROM: James Freeburn at Swinburne University of Technology <jamesfreeburn54(a)gmail.com> James Freeburn (Swinburne/OzGrav), Sarah Teague (UNC), Jonathan Carney (UNC), Igor Andreoni (UNC), Charles Kilpatrick (Northwestern), Olga Volchansky (UMD), Andre Santos (CBPF), Clecio De Bom (CBPF): We continued (Freeburn et al., GCN 39196) follow up observations of the gravitational wave trigger S250206dm (GCN 39175, GCN 39178, GCN 39184, GCN 39231) using the Goodman High Throughput Spectrograph mounted on the SOAR 4.1-meter telescope in imaging mode via Target of Opportunity observations (PI Andreoni). We observed 30 galaxies in the highest probability region (Cook at al. GCN 39174, GCN 39177, GCN 39185, GCN 39235) using the list produced by crossmatching the sky localization with the NED Local Volume Sample (NED-LVS; Cook et al. 2023). Specifically, we considered the galaxy list obtained using the LVK S250206dm-7-Update sky localization (Cook at al. GCN 39235), focusing on the Southern high probability area. Observations were acquired from 2025-02-09 06:48 UT until 09:18 UT. Each galaxy was observed with 3 x 60s exposures in i-band which resulted in a typical depth of ~22 AB magnitude. We used the SOAR/Goodman observations from 2025-02-07 (Freeburn et al. GCN 39196) as science images and the observations from 2025-02-09 as templates. From a preliminary analysis of the resultant difference images, we find one low significance candidate, AT2025ber, at 16:31:50.40 -69:31:44.29, in the 51% localisation contour of the S250206dm updated skymap. It is in the vicinity of the NED-LVS galaxy WISEA J163202.83-693109.0, which is a galaxy with a spectroscopic redshift of z=0.07743 and a luminosity distance of 354.7 Mpc. The separation distance between WISEA J163202.83-693109.0 and AT2025ber is ~100kpc. Given this large separation distance, it is unlikely that WISEA J163202.83-693109.0 is the host galaxy to AT2025ber, but such a large separation would not be unprecedented for a compact binary merger (see, e.g., Fong et al. 2013). The photometry is provided below in AB magnitudes: 2025-02-07 i = 22.0 +/- 0.2 g > 22.4 2025-02-09 i > 22.2 From MPChecker, we do not find any known asteroid associated with AT2025ber. However, given the brightness of this event, and the fact that it was found in a single image, we caution the possibility that this is an uncatalogued asteroid. There is no coincident source in archival DELVE data (Drlica-Wagner et al., 2021) which places upper limits in gri > 23.5 AB mag. A list of the observed galaxies which are still within the 90% probability volume is presented in the table below. The completed pointings were uploaded to TreasureMap: https://treasuremap.space/alerts?graceids=S250206dm object_name coordinates WISEA J161708.84-674024.7 16:17:08.87 -67:40:22.49 WISEA J162759.57-693615.7 16:27:59.57 -69:36:15.71 WISEA J154439.56-665529.0 15:44:39.56 -66:55:29.08 WISEA J155633.83-693531.5 15:56:33.83 -69:35:31.55 WISEA J160843.41-685023.4 16:08:43.41 -68:50:23.44 WISEA J160915.94-690504.9 16:09:15.95 -69:05:04.94 WISEA J161332.77-674621.1 16:13:32.78 -67:46:21.13 WISEA J165614.58-695645.9 16:56:14.58 -69:56:46.00 WISEA J163330.53-670950.7 16:33:30.54 -67:09:50.72 WISEA J154538.24-703944.1 15:45:38.25 -70:39:44.12 WISEA J153057.77-694546.5 15:30:57.77 -69:45:46.58 WISEA J160838.27-700230.8 16:08:38.27 -70:02:30.85 WISEA J161213.79-710729.1 16:12:13.79 -71:07:29.14 WISEA J165744.21-680430.9 16:57:44.21 -68:04:30.93 WISEA J163202.83-693109.0 16:32:02.84 -69:31:09.01 WISEA J164922.44-690054.7 16:49:22.44 -69:00:54.76 WISEA J161735.32-701416.0 16:17:35.32 -70:14:16.00 WISEA J163253.56-702946.2 16:32:53.57 -70:29:46.22 ESO 069- G 003 16:24:32.07 -68:49:12.91 WISEA J161946.23-690837.2 16:19:46.23 -69:08:37.26 WISEA J155653.84-695749.1 15:56:53.88 -69:57:49.18 WISEA J165438.30-670413.8 16:54:38.30 -67:04:13.82 WISEA J163224.97-700239.7 16:32:24.97 -70:02:39.78 WISEA J155231.27-695346.6 15:52:31.31 -69:53:46.61 WISEA J155145.65-695137.1 15:51:45.63 -69:51:36.90 WISEA J154932.61-695540.7 15:49:32.96 -69:55:41.02 WISEA J160323.17-681358.2 16:03:23.27 -68:14:00.31 WISEA J160100.07-690900.0 16:01:00.10 -69:09:00.00 WISEA J161133.67-692644.0 16:11:33.73 -69:26:43.58 WISEA J161459.65-691110.1 16:15:05.66 -69:11:09.89 We thank the NOIRLab and SOAR staff for their excellent support. View this GCN Circular online at https://gcn.nasa.gov/circulars/39286. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37294] LIGO/Virgo/KAGRA S250206dm: Kinder confirmation of a possible artefact in AT 2025bbo
by GCN Circulars 11 Feb '25

11 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39285 SUBJECT: LIGO/Virgo/KAGRA S250206dm: Kinder confirmation of a possible artefact in AT 2025bbo DATE: 25/02/11 14:36:40 GMT FROM: Janet Chen at National Central University <janetstars(a)gmail.com> T.-W. Chen, A. Aryan (both NCU), S. Yang, Z. N. Wang (both HNAS), A. K. H. Kong (NTHU), S. J. Smartt (Oxford/QUB), J. Gillanders (Oxford), A. Sankar. K, Y.-C. Pan, C.-C. Ngeow, M.-H. Lee, Y.-H. Lee, W.-J. Hou, H.-Y. Hsiao, Y. J. Yang, C.-H. Lai, C.-S. Lin, H.-C. Lin, J.-K. Guo (all NCU), L. L. Fan, G. H. Sun (both HNAS), H.-W. Lin (UMich), H. F. Stevance, S. Srivastav, L. Rhodes (all Oxford), M. Nicholl, M. Fulton, T. Moore, K. W. Smith, C. Angus, A. Aamer (all QUB), A. Schultz and M. Huber (both IfA, Hawaii) report: We observed the field of the optical transient AT 2025bbo (Smartt et al., GCN 39244) within the skymap of the NSBH merger event S250206dm (The LIGO-Virgo-KAGRA Collaboration, GCN 39175) as part of the Kinder collaboration (Chen & Yang et al. 2024, arXiv:2406.09270). Observations were conducted using the 1m LOT and 40cm SLT telescopes at Lulin Observatory in Taiwan. In our previous report (Lee et al., GCN 39252), we detected AT 2025bbo using template subtraction based on Pan-STARRS1 reference images (Chambers et al. 2016, arXiv:1612.05560). However, Huber et al. (GCN 39272) noted that the publicly available Pan-STARRS 3Pi reference frame is relatively shallow at the transient’s location. To reassess the detection, we performed additional analyses using different reference images. To verify the flux excess, we employed the Python-based package AutoPhOT (Brennan & Fraser, 2022, A&A, 667, A62) to perform template subtraction using the "sfft" (Hu, 2022, ApJ, 936, 157) and "hotpants" (Becker A., 2015, ascl.soft. ascl:1504.004) alogorithms. Instead of Pan-STARRS1, we used SDSS template images for subtraction. The resulting difference image showed no residual flux at the transient’s position. Additionally, we applied the Kinder pipeline (Yang et al., A&A 646, A22) to subtract stacked images using SDSS templates. The results were consistent with our AutoPhOT analysis, showing no detection of the transient. The details of the observations and measured 3-sigma upper limit (in the AB system) are as follows: Telescope | Filter | MJD | Exposure | Magnitude | avg. Seeing | med. Airmass LOT | r | 60715.463 | 300sec * 6 | > 20.33 | 1".61 | 1.39 LOT | r | 60716.453 | 300sec * 12 | > 21.24 | 1".58 | 1.41 SLT | i | 60716.455 | 300sec * 30 | > 20.33 | 2".53 | 1.68 The presented magnitudes are calibrated using the field stars from the SDSS catalog and are not corrected for the expected Galactic foreground extinction corresponding to a reddening of A_r = 0.24 mag in the direction of the burst (Schlafly & Finkbeiner 2011). We conclude that AT 2025bbo is likely an artefact resulting from the use of a shallow reference image in our previous report. No significant flux excess was found when using SDSS as a reference. View this GCN Circular online at https://gcn.nasa.gov/circulars/39285. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37293] Konus-Wind detection of GRB 250207A
by GCN Circulars 11 Feb '25

11 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39284 SUBJECT: Konus-Wind detection of GRB 250207A DATE: 25/02/11 13:50:11 GMT FROM: Anna Ridnaia at Ioffe Institute <ridnaia(a)mail.ioffe.ru> A. Ridnaia, D. Frederiks, A. Lysenko, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report: The long-duration GRB 250207A (Fermi-GBM detection: Fermi GBM team, GCN 39181; Swift-BAT detection: Ferro et al., GCN 39182; Moss et al., GCN 39245) was detected by Konus-Wind (KW) in the waiting mode. A Bayesian block analysis of the KW waiting mode data reveals a >27 sigma count rate increase in the interval from T0-7.699 s to T0+15.853 s where T0 = T0(BAT) = 01:16:07.33 UT. The KW light curve of this burst is available at http://www.ioffe.ru/LEA/GRBs/GRB250207A/ Modeling a time-integrated spectrum of the burst (from T0-7.699 s to T0+15.853 s) by a power law with exponential cutoff (CPL) model dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep): yields alpha = -1.26 (-0.12, + 0.14) and Ep = 329(-64,+91) keV. The total burst fluence is 1.04(-0.11,+0.13)x10^-5 erg/cm^2, and the 2.944 s peak energy flux, measured from T0+4.077 s, is 7.05(-0.98,+1.08)x10^-7 erg/cm^2. (both in the 20 keV - 10 MeV energy range). All the quoted errors are estimated at the 68% confidence level. All the presented results are preliminary. View this GCN Circular online at https://gcn.nasa.gov/circulars/39284. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37292] Konus-Wind detection of GRB 250206A
by GCN Circulars 11 Feb '25

11 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39283 SUBJECT: Konus-Wind detection of GRB 250206A DATE: 25/02/11 13:48:06 GMT FROM: Anna Ridnaia at Ioffe Institute <ridnaia(a)mail.ioffe.ru> A. Ridnaia, D. Frederiks, A. Lysenko, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report: The long-duration GRB GRB 250206A (Fermi-GBM detection: Fermi GBM team, GCN 39172; BALROG localization: Preis & Greiner, GCN 39173; Fermi-LAT detection: Gupta et al., GCN 39233; EIRSAT-1 GMOD detection: Murphy et al., GCN 39236) triggered Konus-Wind at T0=71491.594 s UT (19:51:31.594). The burst light curve shows two multipeaked episodes started at ~T0-3.6 s with a total duration of ~75.6 s. The emission is seen up to ~4 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB250206_T71491/ As observed by Konus-Wind, the burst had a fluence of 2.44(-0.09,+0.10)x10^-5 erg/cm2, and a 64-ms peak flux, measured from T0+9.072 s, of 2.91(-0.44,+0.44)x10^-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-averaged spectrum of the burst (measured from T0 to T0+73.984 s) is best fit in the 20 keV - 10 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.76(-0.10,+0.11) and Ep = 205(-11,+13) keV (chi2 = 87/98 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2.4 (chi2 = 85/97 dof). The spectrum near the maximum count rate (measured from T0+8.448 to T0+16.640 s) is best fit in the 20 keV - 10 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.06(-0.13,+0.13) and Ep = 223(-9,+10) keV (chi2 = 85/82 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -3.4 (chi2 = 85/81 dof). All the quoted errors are at the 68% confidence level. All the quoted values are preliminary. View this GCN Circular online at https://gcn.nasa.gov/circulars/39283. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37291] GRB 250210A: SVOM/GRM observation of a long burst
by GCN Circulars 11 Feb '25

11 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39282 SUBJECT: GRB 250210A: SVOM/GRM observation of a long burst DATE: 25/02/11 13:03:35 GMT FROM: yqzhang_cl(a)163.com SVOM/GRM team: Yan-Qiu Zhang, Wen-Long Zhang, Shi-Jie Zheng, Wen-Jun Tan, Chen-Wei Wang, Shao-Lin Xiong, Shuang-Nan Zhang (IHEP) SVOM/ECLAIRs team: Frédéric Piron (LUPM), Nicolas Dagoneau (CEA), Maria-Grazia Bernardini (INAF-OAB), Jean-Luc Atteia (IRAP) report on behalf of the SVOM team: SVOM/GRM was triggered in-flight by a long burst GRB 250210A (sb25021009) at 2025-02-10T05:31:56.000 UTC (T0), which was also observed by Fermi/GBM (Fermi GBM team, GCN #39262), AstroSat CZTI (A. Dasgupta et al., GCN #39267) and INTEGRAL/SPI-ACS (P. Barria et al., GCN #39268). With the event-by-event data downloaded through the X-band ground station, the GRM light curve shows that this burst consists of multi-pulses with a T90 of 32.54 +/- 3.62 s in the 15-300 keV band. In addition, the position of this burst, as determined by Fermi/GBM (GCN #39262, RA: 150.3 deg, DEC: -25.5 deg, Error: 2.8 deg), is located at about 52 degrees from the SVOM optical axis, and outside the ECLAIRs field of view. The SVOM/GRM light curve can be found here: https://www.bursthub.cn//admin/static/svgrb250210A.png The Space Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA, China), National Center for Space Studies (CNES, France) and the Chinese Academy of Sciences (CAS, China), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. GRM is developed by the Institute of High Energy Physics (IHEP) of CAS. The SVOM/GRM point of contact for this burst is: Yan-Qiu Zhang (IHEP) (zhangyanqiu(a)ihep.ac.cn) View this GCN Circular online at https://gcn.nasa.gov/circulars/39282. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37290] EP250207b: Liverpool Telescope possible optical counterpart
by GCN Circulars 11 Feb '25

11 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39281 SUBJECT: EP250207b: Liverpool Telescope possible optical counterpart DATE: 25/02/11 10:20:29 GMT FROM: Rob Eyles-Ferris at U of Leicester <raje1(a)leicester.ac.uk> R. A. J. Eyles-Ferris, P. T. O’Brien and R. L. C. Starling (U of Leicester) report: We observed the field of the X-ray transient EP250207b (Zhou et al., GCN 39266) using the IO:O on the 2m Liverpool Telescope. We obtained 5x90s exposures in the SDSS g’ filter starting at 2025-02-10 00:49:54 UT and 5x90s exposures in the SDSS r’ filter starting at 2025-02-10 00:59:10 UT, approximately 74 hours after the X-ray detection. We performed image subtraction on the stacked images using reference images from Pan-STARRS. We identify a possible counterpart in the g’ band subtraction of g’ = 21.24+/-0.14 with photometry calibrated to Pan-STARRS and not corrected for Galactic extinction. The source is located at RA, Dec = 167.51128, -7.87019 deg, which is equivalent to: RA (J2000) : 11:10:02.71 Dec (J2000): -07:52:12.7 This source lies within the error region of the Einstein Probe FXT detection and is the only source within it in our subtracted image. It is consistent with the position of the bright galaxy noted by Malesani et al., GCN 39270 and Levan et al., GCN 39278 with an offset of 0.92 arcsec (1.43 kpc projected) from the position reported by Malesani et al., GCN 39270. In the r’ band subtraction, the source position is obscured by a subtraction artifact and we cannot currently rule out the possibility that the g’ band detection is also an artifact. Further observations to confirm the nature of the source are planned. View this GCN Circular online at https://gcn.nasa.gov/circulars/39281. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37289] EP250207b: Global MASTER-Net observations report
by GCN Circulars 11 Feb '25

11 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39280 SUBJECT: EP250207b: Global MASTER-Net observations report DATE: 25/02/11 09:27:30 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, N.Tiurina, P.Balanutsa, , D.Vlasenko, I.Panchenko, A.Kuznetsov, G.Antipov, A.Sankovich, A.Sosnovskij, Yu.Tselik, M.Gulyaev, Ya.Kechin, V.Senik, A.Chasovnikov, K.Labsina, I. Gorbunov (Lomonosov MSU), O.Gress, N.Budnev (ISU), C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity) D.Buckley (SAAO), R.Rebolo (The Instituto de Astrofisica de Canarias), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory) MASTER-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) was pointed to the EP250207b ( EP Team et al., GCN 39266) errorbox 85997 sec after notice time and 2 days 65886 sec after trigger time at 2025-02-11 09:10:12 UT, with upper limit up to 19.7 mag. Observations started at twilight. The observations began at zenith distance = 46 deg. The sun altitude is -12.9 deg. The galactic latitude b = 47 deg., longitude l = 265 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2774311 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 238716 | 2025-02-11 09:10:12 | MASTER-OAFA | (11h 10m 01.86s , -07d 30m 20.4s) | C | 60 | 19.6 | 238776 | 2025-02-11 09:10:12 | MASTER-OAFA | (11h 10m 01.86s , -07d 30m 20.4s) | C | 180 | 19.7 | Coadd 238791 | 2025-02-11 09:11:26 | MASTER-OAFA | (11h 09m 58.99s , -07d 28m 45.5s) | C | 60 | 19.4 | 238865 | 2025-02-11 09:12:41 | MASTER-OAFA | (11h 09m 59.00s , -07d 30m 13.6s) | C | 60 | 19.1 | 238957 | 2025-02-11 09:13:57 | MASTER-OAFA | (11h 10m 02.25s , -07d 28m 50.3s) | C | 90 | 19.4 | 239064 | 2025-02-11 09:15:45 | MASTER-OAFA | (11h 09m 56.51s , -07d 29m 42.1s) | C | 90 | 19.3 | 239167 | 2025-02-11 09:17:28 | MASTER-OAFA | (11h 09m 56.54s , -07d 28m 41.5s) | C | 90 | 19.2 | 239273 | 2025-02-11 09:19:14 | MASTER-OAFA | (11h 10m 01.95s , -07d 29m 41.2s) | C | 90 | 19.0 | 239378 | 2025-02-11 09:20:59 | MASTER-OAFA | (11h 09m 56.56s , -07d 30m 41.0s) | C | 90 | 18.8 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. View this GCN Circular online at https://gcn.nasa.gov/circulars/39280. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37288] Fermi Gamma-ray Burst Monitor trigger 760945500/250211240 is not a GRB
by GCN Circulars 11 Feb '25

11 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39279 SUBJECT: Fermi Gamma-ray Burst Monitor trigger 760945500/250211240 is not a GRB DATE: 25/02/11 09:03:44 GMT FROM: Marianna Dafčíková at Masaryk University <500025(a)mail.muni.cz> M. Dafcikova (MUNI) reports on behalf of the Fermi Gamma-ray Burst Monitor Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 760945500/250211240 at 05:44:55.61 UT on 11 February 2025, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is likely due to local particles." View this GCN Circular online at https://gcn.nasa.gov/circulars/39279. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37287] Gemini-South spectroscopic redshift of EP250207b host galaxy candidate (z=0.082)
by GCN Circulars 11 Feb '25

11 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39278 SUBJECT: Gemini-South spectroscopic redshift of EP250207b host galaxy candidate (z=0.082) DATE: 25/02/11 08:35:07 GMT FROM: Andrew Levan at Radboud University <a.levan(a)astro.ru.nl> Andrew J. Levan (Radboud), Daniele B. Malesani (DAWN/NBI and Radboud), Peter G. Jonker (Radboud), Jonathan A. Quirola-Vásquez (Radboud), Javi Sánchez-Sierras (Radboud), Antonio Martin-Carrillo (UCD), Franz E. Bauer (PUC), report on behalf of a larger collaboration: We obtained spectroscopic observations of the candidate host galaxy WISEA J111002.65-075211.9 of EP 250207b (Zhou et al., GCN 39266) with the Gemini South telescope and the GMOS spectrograph. A total of 4x180 s observations were obtained, covering the spectral range 3600-7600 AA, with a mean time of about 3.3 days after the high-energy transient. The spectrum is clearly that of a quiescent galaxy with no detectable emission lines. From a provisional reduction, we identify the presence of Ca H&K, Mg I, and Na I D absorption and determine a redshift of z = 0.082. The galaxy is unlike those of collapsar GRBs, consistent with the non-detection of any counterpart in deep imaging (Malesani et al. GCN 39270), which also rules out any FBOT-like emission similar to that seen in other recent FXTs. If this is the host of EP 250207b a possibility is that the transient was created via a compact object merger. However, given the large (10” radius) X-ray error localisation we caution that an origin in a higher redshift system in chance projection to the z=0.082 galaxy remains plausible. We encourage further observations to search for the optical/IR counterpart. We thank the staff of Gemini, in particular Jeong-Eun Heo, for their excellent support in securing these observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/39278. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37286] LIGO/Virgo/KAGRA S250211be: Identification of a GW compact binary merger candidate
by GCN Circulars 11 Feb '25

11 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39277 SUBJECT: LIGO/Virgo/KAGRA S250211be: Identification of a GW compact binary merger candidate DATE: 25/02/11 04:56:55 GMT FROM: Hisaaki Shinkai at Osaka Institute of Technology <hisaaki.shinkai(a)oit.ac.jp> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S250211be during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2025-02-11 04:35:43.152 UTC (GPS time: 1423283761.152). The candidate was found by the CWB BBH [1], GstLAL [2], and MBTA [3] analysis pipelines. S250211be is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.8e-08 Hz, or about one in 1 year, 9 months. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S250211be After parameter estimation by RapidPE-RIFT [4], the classification of the GW signal, in order of descending probability, is BBH (99%), Terrestrial (1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [5] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [5] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 32 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 1530 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3638 +/- 1204 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] T. Mishra et al. PRD 105, 083018 (2022) doi:10.1103/PhysRevD.105.083018 [2] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [3] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [4] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002 [5] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [6] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013 View this GCN Circular online at https://gcn.nasa.gov/circulars/39277. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37285] LIGO/Virgo/KAGRA S250211aa: Updated Sky localization and EM Bright Classification
by GCN Circulars 11 Feb '25

11 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39276 SUBJECT: LIGO/Virgo/KAGRA S250211aa: Updated Sky localization and EM Bright Classification DATE: 25/02/11 04:44:56 GMT FROM: Soichiro Morisaki at U. of Tokyo <soichiro.morisaki(a)ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S250211aa (GCN Circular 39275). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S250211aa Based on posterior support from parameter estimation [1], under the assumption that the candidate S250211aa is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 248 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1121 +/- 258 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380 [2] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe View this GCN Circular online at https://gcn.nasa.gov/circulars/39276. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37284] LIGO/Virgo/KAGRA S250211aa: Identification of a GW compact binary merger candidate
by GCN Circulars 11 Feb '25

11 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39275 SUBJECT: LIGO/Virgo/KAGRA S250211aa: Identification of a GW compact binary merger candidate DATE: 25/02/11 02:51:13 GMT FROM: Allen1711449(a)gmail.com The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S250211aa during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2025-02-11 02:25:46.623 UTC (GPS time: 1423275964.623). The candidate was found by the CWB [1], CWB BBH [2], GstLAL [3], MBTA [4], and PyCBC Live [5] analysis pipelines. S250211aa is an event of interest because its false alarm rate, as estimated by the online analysis, is 4.7e-18 Hz, or about one in 1e10 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S250211aa After parameter estimation by RapidPE-RIFT [6], the classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [7] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [7] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 34 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 356 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1358 +/- 352 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] T. Mishra et al. PRD 105, 083018 (2022) doi:10.1103/PhysRevD.105.083018 [3] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [4] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [5] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [6] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002 [7] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [8] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013 View this GCN Circular online at https://gcn.nasa.gov/circulars/39275. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37283] GRB 250207A: Skynet optical afterglow observations
by GCN Circulars 11 Feb '25

11 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39274 SUBJECT: GRB 250207A: Skynet optical afterglow observations DATE: 25/02/11 01:35:36 GMT FROM: dschlekat(a)unc.edu Donovan Schlekat, Dylan Dutton, Daniel Reichart, Joshua Haislip, and Vladimir Kouprianov report on behalf of the Skynet Robotic Telescope Network at the University of North Carolina at Chapel Hill. We observed the field of GRB 250207A detected by Fermi (The Fermi GBM Team, GCN 39181) and Swift (Ferro et al., GCN 39182; Osborne et al., GCN 39217; Melandri et al., GCN 39221; Moss et al., GCN 39245) with two of Skynet's PROMPT telescopes located at the Cerro Tololo Inter-American Observatory. The observation began at 01:20:03 UT on February 7 2025, roughly 4 minutes after the Swift-BAT trigger and lasted for around 14 minutes until the field was no longer observable. Observations were performed in the B, V, R, and I bands. Exposure lengths were calculated using our automated exposure length scaling model. We detect the optical afterglow (Ferro et al., GCN 39182; Angulo et al., GCN 39186; Kuin & Ferro, GCN 39199; Brivio et al., GCN 39202; Jelinek et al., GCN 39209; Ferro et al., 39212; Ror et al., 39250) in the V, R, and I bands. The photometry of the initial detection for each band is reported below. Tmid - T0 (s)| Telescope | Filter | Exposure (s) | Mag | Mag Error ------------------------------------------------------------------ 747.0 | PROMPT-6 | V | 22 | 16.854 | 0.064 779.0 | PROMPT-5 | R | 16 | 16.593 | 0.097 805.0 | PROMPT-6 | I | 10 | 16.570 | 0.061 Our images have been calibrated using stars from the APASS catalog. Magnitudes were not corrected for dust extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/39274. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37282] LIGO/VIRGO/KAGRA S250206dm: AT 2025bbo spectroscopic observations with NIRES on Keck II
by GCN Circulars 11 Feb '25

11 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39273 SUBJECT: LIGO/VIRGO/KAGRA S250206dm: AT 2025bbo spectroscopic observations with NIRES on Keck II DATE: 25/02/11 01:04:26 GMT FROM: Viraj Karambelkar at Indian Inst of Tech,Bombay <karambelkarvraj21197(a)gmail.com> Viraj Karambelkar (Caltech), Tomas Ahumada (Caltech), Sam Rose (Caltech), Kaew Tinyanont (NARIT), Christoffer Fremling (Caltech), Nicholas Earley (Caltech), and Mansi Kasliwal (Caltech) report: We observed the transient AT2025bbo (GCN 39210; 39244) with the Near-Infrared Echelle Spectrograph (NIRES, Wilson et al. 2004) on the Keck II telescope on 2025-02-10 05:29:43 UTC. Our observations comprised six exposures of 300s each. The spectra were extracted using the idl package spextool (Cushing et al. 2003, Vacca et al. 2004) The spectrum shows several absorption features attributable to the host galaxy (CN, Mg I, Si I, CO absorption) at a redshift of z=0.070+/-0.001, consistent with the redshift reported in GCN 39272. No obvious features attributable to a supernova or AGN are visible. Further analysis is in progress. We thank the Keck Observatory staff (Carlos Alvarez and Rita) and the Keck II observers (Maissa Salama and Becky Jensen-Clem) for their cooperation with the Target of Opportunity observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/39273. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37281] LIGO/Virgo/KAGRA S250206dm: Gemini-North spectroscopic observation of AT2025bbo and its host galaxy
by GCN Circulars 11 Feb '25

11 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39272 SUBJECT: LIGO/Virgo/KAGRA S250206dm: Gemini-North spectroscopic observation of AT2025bbo and its host galaxy DATE: 25/02/11 00:33:06 GMT FROM: James Gillanders at University of Oxford <jhgillanders.astro(a)gmail.com> M. E. Huber (IfA, University of Hawaii), J. H. Gillanders (Oxford), K. Chambers (IfA, University of Hawaii), S. J. Smartt (Oxford), M. Fulton (QUB), T.-W. Chen (NCU) and D. Magill (QUB) report on behalf of a larger collaboration: We observed the transient AT2025bbo and its host galaxy with the GMOS-N spectrograph at the Gemini-North observatory under observing program ID GN-2025A-Q-133 (PI: M. E. Huber). AT2025bbo is a transient discovered during the Pan-STARRS coverage (Young et al., GCN 39210; Smartt et al., GCN 39244) of the skymap of S250206dm, the NSBH merger event detected by the LIGO-Virgo-KAGRA (LVK) Collaboration (GCN 39175). Our epoch of observation commenced at 2025-02-10 05:44 UTC, corresponding to approximately 3.35 days after the recorded merger signal of S250206dm (LVK Collaboration, GCN 39175). We obtained 4x1200s exposures with the R400 grating, sampling a wavelength range of ~4500-9200 angstroms. The source is coincident with the nucleus of the host galaxy (Smartt et al., GCN 39244), and we extracted a spectrum which would contain both the host light and any transient flux within the slit aperture. The spectrum is that of an early-type, elliptical galaxy, consistent with the Pan-STARRS and SDSS colours. The redshift from the Mg I and Na I lines is z = 0.070 +/- 0.006 (D_L = 316 Mpc for H0 = 70 km/s/Mpc). This confirms that the galaxy lies within the estimated luminosity distance range for S250206dm from the Bilby 3D skymap (373 +/- 104 Mpc; LVK Collaboration, GCN 39231). The continuum of the spectrum does not show any obvious broad features from transient flux, nor any emission lines (e.g., H-alpha, [O III]) from AGN activity. It appears consistent with galaxy light, but further analysis is required to determine if any continuum from a transient source is present. In Smartt et al. (GCN 39244), we advised caution on the reality of this event. Detections of AT2025bbo were reported by three other teams: Liu et al. (GCN 39429), Lee et al. (GCN 39252), and Ducoin et al. (GCN 39258). Upon further investigation, we find that the publicly available Pan-STARRS 3Pi reference frame (which all teams used to subtract the host) consists of only 2x40s frames at this location. While the header of the reference stack implies 24x40s, there is significant masking in the input images around the transient/galaxy position. This can be seen by selecting the warp option in the MAST user interface to access the image stamps, to display all 24 warp images. Liu et al. (GCN 39429) also reported an i-band detection, which has a good Pan-STARRS reference (630s total). Further work is required to determine if the flux excess, which all four teams detect, is due to transient flux on the galaxy core, or an artefact of the shallow reference r-band image. We thank the staff of the Gemini Observatory for rapidly approving and executing these observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/39272. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37280] GRB 241128A: VIRT Optical Upper Limit
by GCN Circulars 10 Feb '25

10 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39271 SUBJECT: GRB 241128A: VIRT Optical Upper Limit DATE: 25/02/10 20:27:27 GMT FROM: Priya Gokuldass at ERAU <gokuldap(a)my.erau.edu> R. Querrard (UVI), P. Gokuldass (ERAU), N. Orange (OrangeWave Innovative Science, LLC), B. Gendre (UVI), D. Morris (NASA), T. Lombardi (Eckerd College), F. George (ERAU), D. Smith (UVI), K. Smith (UVI), C. Watson (UVI) report: We observed the field of GRB241128A (Brivio et al., GCN 38367) with the 0.5m Virgin Island Robotic Telescope (VIRT) at the University of the Virgin Islands' Etelman Observatory on 2024-11-29 starting at 22:47:51.703 (T-mid ~ T0 + 30.75 hrs). We performed a series of exposures in an R filter with a total exposure of 1370s. The weather conditions were partly cloudy during the hours of observation with an average airmass of 2.94. We do not detect any source within the enhanced XRT position (Beardmore et al. GCN 38374). This non-detection is consistent with reported detections (Hu et al., GCN 38371;Izzo et al., GCN 38372; Gompertz et al., GCN 38373; Akl et al., GCN 38382; Pankov et al., GCN 38383; Midavaine et al., GCN 38438; and Volnova et al., GCN 38519 ) and upper limits (Lipunov et al., GCN 38380; Shilling et al., GCN 38422; Akl et al., GCN 38382; Pankov et al., GCN 38395; Midavaine et al., GCN 38438; and Volnova et al., GCN 38519 ). We report the following 3-sigma upper limit: T_mid ||Exposure ||Filter ||Limit T+30.75 hrs || 1370 s || R || > 18.6 The limit is estimated from comparison to nearby USNO B1 stars and is not corrected for Galactic extinction. We acknowledge financial support from NASA EPSCoR award 80NNSC22M0063, NSF PAARE award 2319415, and NASA EPSCoR award 80NSSC24M0112. This message can be cited. View this GCN Circular online at https://gcn.nasa.gov/circulars/39271. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37279] EP250207b: Gemini GMOS-N z-band observations
by GCN Circulars 10 Feb '25

10 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39270 SUBJECT: EP250207b: Gemini GMOS-N z-band observations DATE: 25/02/10 17:04:14 GMT FROM: P.G. Jonker at Radboud University <p.jonker(a)astro.ru.nl> Daniele B. Malesani (DAWN/ NBI and Radboud), Andrew J. Levan (Radboud), Jonathan Quirola-Vásquez (Radboud), Peter G. Jonker (Radboud), Javi Sánchez-Sierras (Radboud), Franz Bauer (PUC) report on behalf of a larger collaboration: We obtained photometric observations of the field of the fast X-ray transient EP250207b discovered by Einstein Probe (Zhou et al., GCN 39266) with the GMOS instrument mounted on the Gemini-North telescope (PI: F. Bauer; program GN-2024B-FT-112). We obtained 6 images with 15 s exposure time each and 6 with an exposure time of 60 s each in the z-band filter beginning at 2025-02-10 10:40 UT, approximately 2.5 days after the EP/WXT trigger. Within the EP/FXT error circle, comparing our stacked image with Legacy archival images we detect no plausible optical counterpart down to the depth of the Legacy Survey observations. Image subtraction between the GMOS and the Legacy Survey data also reveals no new sources. We do note the presence of a bright galaxy within the FXT error circle. This galaxy lies at RA(J2000) = 11:10:02.67 DEC(J2000) = -07:52:12.0 and has an r-band magnitude of r = 17.2. The galaxy is detected but WISE but it is not in ALLWISEAGN, implying it is unlikely to be an AGN. Following the prescription of Bloom et al. 2002 (doi: https://link.springer.com/article/10.1007/s41114-019-0024-0) we find a probability of 0.5% of such a galaxy lying within the FXT error circle by chance. The galaxy has a photometric redshift of z = 0.074+-0.009 from Legacy Survey (Zhou et al. 2021, doi:10.1093/mnras/staa3764). We thank the staff of Gemini for their excellent support in securing these observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/39270. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37278] EP250207A: Upper limits from Fermi-GBM Observations
by GCN Circulars 10 Feb '25

10 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39269 SUBJECT: EP250207A: Upper limits from Fermi-GBM Observations DATE: 25/02/10 15:39:25 GMT FROM: mariaedvige.ravasio(a)ru.nl M. E. Ravasio (Radboud Univ.), E. Burns (LSU), and P.G. Jonker (Radboud Univ.) report on behalf of the Fermi-GBM Team: Fermi-GBM had full spatial coverage of the transient EP250207A detected by EP-WXT (Li et al., GCN 39224), identified as a stellar flare (Levan et al., GCN 39218, O'Connor et al., GCN 39219, Li et al., GCN 39224). There was no Fermi-GBM onboard trigger around the EP trigger time T0=2025-02-07T15:51:17 UTC. The GBM targeted search [1], the most sensitive, coherent search for GRB-like signals, was run in the time interval [T0-50;T0+500] s, seeking signals between 64 ms and 32.768 s in duration. No signal consistent with the EP transient both temporally and spatially is identified, as confirmed by visual inspection of the data. Assuming a “soft” spectral template (Band function with Epeak = 70 keV, alpha = -1.9, beta = -3.7), and a duration of 8.192 s, we derive a sky-averaged flux upper limit of 2.8e-08 erg/cm2/s in the energy band 10-1000 keV. [1] Goldstein et al. 2019 arXiv:1903.12597 View this GCN Circular online at https://gcn.nasa.gov/circulars/39269. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37277] GRB 250210A: INTEGRAL SPI-ACS detection
by GCN Circulars 10 Feb '25

10 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39268 SUBJECT: GRB 250210A: INTEGRAL SPI-ACS detection DATE: 25/02/10 11:08:10 GMT FROM: Aishwarya L Thakur at INAF-IAPS, Rome <aishth(a)outlook.com> Patrizia Barria(a,b), Giulia Gianfagna(a), James Craig Rodi(a), Aishwarya Linesh Thakur(a), Lorenzo Natalucci(a,b), Luigi Piro(a) report: GRB 250210A was discovered by Fermi/GBM (GCN 39262, seen also by AstroSat/CZTI GCN 39267) on 2025-02-10T05:31:40 (UTC). We searched for a corresponding counterpart in the INTEGRAL/SPI-ACS data. In an SPI-ACS light curve above 80 keV, we find a signal temporally coincident with the GBM detection, having an approximate duration of ~ 40 sec. The signal consists of two pulses over this duration. The approximate peak count rate in SPI-ACS is 67,700 cts/s for E>80 keV, over a median background rate of 63,324 cts/s. This work is based on observations with INTEGRAL, an ESA project with instruments and a science data centre funded by ESA member states (especially the PI countries: Denmark, France, Germany, Italy, Switzerland, and Spain), and with the participation of Russia and the USA. The SPI-ACS detector system has been provided by MPE Garching/Germany. ----- (a) INAF/IAPS-Rome (b) ICSC National Research Centre for High-Performance Computing View this GCN Circular online at https://gcn.nasa.gov/circulars/39268. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37276] GRB 250210A: AstroSat CZTI detection
by GCN Circulars 10 Feb '25

10 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39267 SUBJECT: GRB 250210A: AstroSat CZTI detection DATE: 25/02/10 10:39:26 GMT FROM: Gaurav Waratkar at IIT Bombay <gauravwaratkar(a)iitb.ac.in> A. Dasgupta (BITS Pilani, Hyderabad), G. Waratkar (IITB), J. Joshi (IUCAA), A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka University/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration: Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 2021, JApA, 42, 73) showed the detection of a long-duration GRB 250210A which was also detected by Fermi/GBM (Fermi-GBM Team, GCN Circ. 39262). Inspection of INTEGRAL/SPI-ACS data also showed the detection of the burst. The source was clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2025-02-10 05:31:58.0 UTC. The measured peak count rate is 293 (+69, -41) counts/s above the background in the combined Veto data of all quadrants, with a total of 4599 (+645, -696) counts. The local mean background count rate was 1317 (+7, -7) counts/s. We measure a T90 of 29 (+2, -2) s from the cumulative Veto light curve. The source was also faintly detected in the CZT detectors in the 20-200 keV energy range. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research Organisation funded, managed, and facilitated the project. CZTI GRB detections are reported regularly on the payload site at: http://astrosat.iucaa.in/czti/?q=grb View this GCN Circular online at https://gcn.nasa.gov/circulars/39267. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37275] EP250207b: a new X-ray transient detected by Einstein Probe
by GCN Circulars 10 Feb '25

10 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39266 SUBJECT: EP250207b: a new X-ray transient detected by Einstein Probe DATE: 25/02/10 09:16:09 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> X.-Y. Zhou (PRIC), A. Li (BNU), D.-H. Zhao, X.-P. Xu, Q.-Y. Wu and Y. Liu (NAOC, CAS) report on behalf of the Einstein Probe team: We report on the detection of an X-ray transient, designated EP250207b, by the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP) mission. The transient event started at T0=2025-02-07T21:47:56(UTC) and lasted for more than 120 s before the observation ended. The WXT position of the source is R.A. = 167.495 deg, DEC = -7.906 deg (J2000) with an uncertainty of 2.7 arcmin in radius (90% C.L. statistical and systematic). The average WXT 0.5-4 keV spectrum can be fitted with an absorbed power law with a fixed Galactic equivalent hydrogen column density of 4.24 x 10^20 cm^-2 and a photon index of 0.6 (-0.8/+0.8). The derived average unabsorbed 0.5-4 keV flux is 6.1 (-2.5/+4.2) x 10^(-10) erg/s/cm^2. Two ToO observations were performed by the Follow-up X-ray Telescope (FXT) . The first observation started at 2025-02-08T14:52:06 (~T0+17h) with an exposure time of 3024 s. An uncatalogued source was detected at R.A. = 167.5130, DEC = -7.8695 (J2000) with an uncertainty of 10 arcsec (radius, 90% C.L. statistical and systematic). The average FXT 0.5-10 keV spectrum can be fitted with an absorbed power law with a fixed Galactic equivalent hydrogen column density of 4.24 x 10^20 cm^-2 and a photon index of 1.5 (-0.6/+0.6), giving an average unabsorbed 0.5-10 keV flux of 3.6 (-1.4/+3.5) x 10^(-13) erg/s/cm^2. The second observation started at 2025-02-09T18:10:59 (~T0+44h) with an exposure time of 5042 s. The uncatalogued source was detetcted with a declined flux of 6.4 (-2.8/+3.5) x 10^(-14) erg/s/cm^2, indicating its correlation with EP250207b. The uncertainties are at the 90% confidence level for the above parameters. Further follow-up observations are encouraged to identify the nature of this X-ray transient. Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). View this GCN Circular online at https://gcn.nasa.gov/circulars/39266. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37274] LIGO/Virgo/KAGRA S250206dm: MASTER detection AT2025bbo
by GCN Circulars 10 Feb '25

10 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39265 SUBJECT: LIGO/Virgo/KAGRA S250206dm: MASTER detection AT2025bbo DATE: 25/02/10 09:10:56 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, A.Kuznetsov, N.Tiurina, D.Vlasenko, P.Balanutsa, I.Panchenko, A.Chasovnikov K.Zhirkov, G.Antipov, A.Sankovich, I.Gorbunov, A.Sosnovskij, Yu.Tselik, Ya.Kechin, V.Senik, V.Topolev (Lomonosov MSU), O.Gress, N.Budnev, O.Ershova (ISU), C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), D.Buckley (SAAO), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity), R.Rebolo (The Instituto de Astrofisica de Canarias), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory) Global MASTER robotic net (Applied Physics Institute, ISU, Lipunov, Korniov, Gorbovskoy, Tiurina & Kuznetsov, 2023, Astronomical Robotic Networks and Operative Multichanel Astrophysics, Lomonosov MSU PRESS, 591 pp. https://msupress.com/en/catalogue/books/book/astronomicheskie-robotizirovan…) detected OT AT2025bbo (Smart et al., GCN 39244) in GW LVK error area S250206dm (The LIGO-Virgo-Kagra Collaboration, GCN 39175) with 19.1 unfiltered magnitude at 2025-02-09 16:54:16 (exp = 1440 sec).. The deep image is welcome. View this GCN Circular online at https://gcn.nasa.gov/circulars/39265. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37273] GRB 250209A: MAXI/GSC detection (possible detection of an X-ray flare from 1RXS J145110.3+310648)
by GCN Circulars 10 Feb '25

10 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39264 SUBJECT: GRB 250209A: MAXI/GSC detection (possible detection of an X-ray flare from 1RXS J145110.3+310648) DATE: 25/02/10 06:51:48 GMT FROM: Hitoshi Negoro at Nihon University/MAXI team <negoro.hitoshi(a)nihon-u.ac.jp> H. Negoro, H. Nishio (Nihon U.), T. Mihara (RIKEN), M. Serino (AGU), M. Nakajima, Y. Kudo, H. Shibui, K. Takagi, H. Takahashi, K. Tatano (Nihon U.), S. Yamada, T. Tamagawa, N. Kawai, M. Matsuoka (RIKEN), T. Sakamoto, S. Sugita, Y. Kawakubo, H. Hiramatsu, H. Nishikawa, Y. Kondo, S. Sasao, A. Yoshida (AGU), Y. Tsuboi, H. Sugai, N. Nagashima (Chuo U.), M. Shidatsu, Y. Niida (Ehime U.), I. Takahashi, M. Niwano, N. Higuchi, Y. Yatsu (Tokyo Tech), S. Nakahira, S. Ueno, H. Tomida, M. Ishikawa, S. Ogawa, M. Kurihara (JAXA), Y. Ueda, Y. Okada, K. Fujiwara (Kyoto U.), M. Yamauchi, Y. Otsuki, T. Hasegawa, M. Nishio (Miyazaki U.), K. Yamaoka (Nagoya U.), M. Sugizaki (Kanazawa U.), W. Iwakiri (Chiba U.), T. Kawamuro (Osaka U.), report on behalf of the MAXI team: The MAXI/GSC detected a relatively soft X-ray transient source at 11:00 UT on February 9, 2025. Assuming that the source flux was constant over the transit, we obtain the source position at (R.A., Dec) = (222.844 deg, 30.986 deg) = (14 51 22, +30 59 09) (J2000) with a statistical 90% C.L. elliptical error region with long and short radii of 0.35 deg and 0.32 deg, respectively. The roll angle of the long axis from the north direction is 54.0 deg counterclockwise. There is an additional systematic uncertainty of 0.1 deg (90% containment radius). The X-ray flux averaged over the scan was 133 +- 34 mCrab (4.0-10.0keV, 1 sigma error). Without assumptions on the source constancy, we obtain a rectangular error box for the transient source with the following corners: (R.A., Dec) = (221.544, 29.670) deg = (14 46 10, +29 40 12) (J2000) (R.A., Dec) = (222.164, 29.349) deg = (14 48 39, +29 20 56) (J2000) (R.A., Dec) = (223.910, 31.810) deg = (14 55 38, +31 48 35) (J2000) (R.A., Dec) = (223.280, 32.140) deg = (14 53 07, +32 08 24) (J2000) There was no significant excess flux in the previous transit at 09:27 UT and in the next transit at 12:33 UT with an upper limit of 20 mCrab for each. This transient event is positionally consistent with a nearby M4.0Ve star G 166-49 (a.k.a. 1RXS J145110.3+310648) and GRB 190306A (GCN Circ. 23937, 23941). This and the relatively soft X-ray spectrum suggest that this event originates from an X-ray flare from G 166-49. If so, the luminosity of the flare is about 6.0e31 erg/cm2/s for 13 pc distance, and that GRB 190306A might be an X-ray flare from this source though GRB 190306A showed a harder spectrum. We also designates this event GRB 250209A because of the un-identification. We crosspost this to the ATel and the GCN Circular for both communities. View this GCN Circular online at https://gcn.nasa.gov/circulars/39264. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37272] Fermi GRB 250210A: Global MASTER-Net observations report
by GCN Circulars 10 Feb '25

10 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39263 SUBJECT: Fermi GRB 250210A: Global MASTER-Net observations report DATE: 25/02/10 05:46:02 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, N.Tiurina, P.Balanutsa, , D.Vlasenko, I.Panchenko, A.Kuznetsov, G.Antipov, A.Sankovich, A.Sosnovskij, Yu.Tselik, M.Gulyaev, Ya.Kechin, V.Senik, A.Chasovnikov, K.Labsina, I. Gorbunov (Lomonosov MSU), O.Gress, N.Budnev (ISU), C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity) D.Buckley (SAAO), R.Rebolo (The Instituto de Astrofisica de Canarias), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory) MASTER-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) started inspect of the Fermi GRB 250210A ( Fermi GBM team, GCN 39262) errorbox 87 sec after notice time and 123 sec after trigger time at 2025-02-10 05:33:43 UT, with upper limit up to 19.3 mag. The observations began at zenith distance = 6 deg. The sun altitude is -43.4 deg. The galactic latitude b = 23 deg., longitude l = 262 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2774098 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 133 | 2025-02-10 05:33:43 | MASTER-OAFA | (09h 54m 55.98s , -29d 23m 26.3s) | C | 20 | 17.7 | 133 | 2025-02-10 05:33:43 | MASTER-OAFA | (10h 05m 22.08s , -28d 58m 37.7s) | C | 20 | 19.2 | 175 | 2025-02-10 05:34:29 | MASTER-OAFA | (10h 00m 11.61s , -27d 39m 32.1s) | C | 10 | 17.1 | 185 | 2025-02-10 05:34:30 | MASTER-OAFA | (10h 10m 27.82s , -27d 14m 47.7s) | C | 30 | 19.3 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. View this GCN Circular online at https://gcn.nasa.gov/circulars/39263. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37271] GRB 250210A: Fermi GBM Final Real-time Localization
by GCN Circulars 10 Feb '25

10 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39262 SUBJECT: GRB 250210A: Fermi GBM Final Real-time Localization DATE: 25/02/10 05:42:14 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply(a)GIOC.nsstc.nasa.gov> The Fermi GBM team reports the detection of a likely LONG GRB At 05:31:40 UT on 10 Feb 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250210A (trigger 760858305.125996 / 250210230). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 150.3, Dec = -25.5 (J2000 degrees, equivalent to J2000 10h 01m, -25d 30'), with a statistical uncertainty of 2.8 degrees. The angle from the Fermi LAT boresight is 30.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250210230/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250210230/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250210230/… View this GCN Circular online at https://gcn.nasa.gov/circulars/39262. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37270] LIGO/Virgo/KAGRA S250206dm: Upper limits from GECAM Observations
by GCN Circulars 10 Feb '25

10 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39261 SUBJECT: LIGO/Virgo/KAGRA S250206dm: Upper limits from GECAM Observations DATE: 25/02/10 03:19:49 GMT FROM: yqzhang_cl(a)163.com Ce Cai (HEBNU), Shao-Lin Xiong, Yan-Qiu Zhang, Wen-Jun Tan, Chen-Wei Wang, Yue Wang and Jin-Peng Zhang (IHEP) report on behalf of the GECAM team: At the event time 2025-02-06T21:25:30.439 (UTC) of S250206dm (GCN 39175; GCN 39178; GCN 39231), GECAM-C was observing normally and monitored 66.9% of the localization probability region of this GW event, while GECAM-A and GECAM-B detectors were turned off. There was no GECAM-C in-flight trigger around the event time of S250206dm. The routine blind search of GECAM-C data also found no burst candidate. Thus, we implemented a targeted search [1] within +/-30 s around the event time, and identified no candidate above 3 sigma. Considering three typical GRB spectral models (i.e. soft, normal and hard Band functions), three timescales and the center region of GW localization (RA= 38.21°, Dec = 53.47°), the 3 sigma upper limits of the GRB energy flux (10 keV-1000 keV, in units of 10^-7 erg/s/cm^2) are reported below: Timescale (s) Soft Normal Hard 0.1 1.84 2.33 4.10 1 0.58 0.73 1.29 10 0.18 0.23 0.41 With the median luminosity distance of 373 Mpc from the GW detection (GCN 39231), we further calculate the following upper limits of the GRB intrinsic luminosity (1 keV-10 MeV, in units of 10^49 erg/s): Timescale (s) Soft Normal Hard 0.1 0.46 0.55 3.39 1 0.14 0.17 1.06 10 0.05 0.05 0.33 We note that all these results are preliminary and refined analysis will be reported. Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) mission originally consists of two micro-satellites (GECAM-A and GECAM-B) launched in Dec. 2020. As the third member of GECAM constellation, GECAM-C was launched onboard SATech-01 experimental satellite in July 2022. GECAM mission is funded by the Chinese Academy of Sciences (CAS). [1] C. Cai et al. MNRAS 508, 3910–3920 (2021) https://doi.org/10.1093/mnras/stab2760 View this GCN Circular online at https://gcn.nasa.gov/circulars/39261. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37269] IceCube-250207A: Upper limits from a search for additional neutrino events in IceCube
by GCN Circulars 09 Feb '25

09 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39260 SUBJECT: IceCube-250207A: Upper limits from a search for additional neutrino events in IceCube DATE: 25/02/09 22:02:46 GMT FROM: Alicia Mand at IceCube/UW-Madison <aemand(a)wisc.edu> The IceCube Collaboration (http://icecube.wisc.edu/) reports: IceCube has performed a search [1] for additional track-like muon neutrino events arriving from the direction of IceCube-250207A (https://gcn.nasa.gov/circulars/39203) in a time range of 1000 seconds centered on the alert event time (2025-02-07 01:59:35.270 UTC to 2025-02-07 02:16:15.270 UTC) during which IceCube was collecting good quality data. Excluding the event that prompted the alert, zero track-like events are found within the 90% containment region of IceCube-250207A. The IceCube sensitivity to neutrino point sources with an E^-2.5 spectrum (E^2 dN/dE at 1 TeV) within the locations spanned by the 90% spatial containment region of IceCube-250207A is 1.4e-01 GeV cm^-2 in a 1000 second time window. 90% of events IceCube would detect from a source at this declination with an E^-2.5 spectrum have energies in the approximate energy range between 2e+02 GeV and 9e+04 GeV. A subsequent search was performed including 2 days of data centered on the alert event time (2025-02-06 02:07:55.270 UTC to 2025-02-08 02:07:55.270 UTC). In this case, we report a p-value of 0.20, consistent with no significant excess of track events. The IceCube sensitivity to neutrino point sources with an E^-2.5 spectrum (E^2 dN/dE at 1 TeV) within the locations spanned by the 90% spatial containment region of IceCube-250207A is 1.7e-01 GeV cm^-2 in a 2 day time window. The IceCube Neutrino Observatory is a cubic-kilometer neutrino detector operating at the geographic South Pole, Antarctica. The IceCube realtime alert point of contact can be reached at roc(a)icecube.wisc.edu. [1] IceCube Collaboration, R. Abbasi et al., ApJ 910 4 (2021) View this GCN Circular online at https://gcn.nasa.gov/circulars/39260. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37268] LIGO/Virgo/KAGRA S250206dm: COLIBRÍ/DDRAGO Observations of AT2025bbo and Galaxies in the Localization Volume
by GCN Circulars 09 Feb '25

09 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39258 SUBJECT: LIGO/Virgo/KAGRA S250206dm: COLIBRÍ/DDRAGO Observations of AT2025bbo and Galaxies in the Localization Volume DATE: 25/02/09 20:50:19 GMT FROM: Alan Watson at UNAM <alan(a)astro.unam.mx> Jean-Grégoire Ducoin (CPPM), Rosa L. Becerra (U Rome), Dalya Akl (AUS), Alan M. Watson (UNAM), Ny Avo Rakotondrainibe (LAM), Sarah Antier (OCA), Stéphane Basa (UAR Pytheas), William H. Lee (UNAM), Camila Angulo (UNAM), Jean-Luc Atteia (IRAP), Nathaniel R. Butler (ASU), Damien Dornic (CPPM), Francis Fortin (IRAP), Noémie Globus (UNAM), Francesco Magnani (CPPM), Margarita Pereyra (UNAM), and Benjamin Schneider (LAM) report: We imaged the field of the candidate reported by the Pan-STARRS Collaboration (Young et al. GCN 39210) of the optical transient AT 2025bbo reported as a possible counterpart of the GW transient S250206dm (LVK Collaboration, GCN Circ. 39175, GCN Circ. 39184) with the DDRAGO wide-field imager on the COLIBRÍ telescope at the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir in Mexico. We observed AT 2025bbo from 2025-02-09 03:47 to 04:44 (from T+2.27 to T+2.30 days after the GW transient), obtaining 600 seconds of exposure in both g and r. The data were reduced and stacked using custom software and then calibrated against the PS1 catalog and analysed using STDPipe (Karpov 2021). We carried out image subtraction against PS DR2 images. At the position of the source reported by Young et al., we detect the source at: r = 19.85 +/- 0.05 In agreement to the increase in the brightness reported by the Kinder (Lee et al., GCN Circ. 39252) and WFST collaborations (Smartt et al., GCN Circ. 39249). In g, the source is fainter than our 3-sigma limit of g > 21.1 This suggests that the source is red. Further observations are planned. Furthermore, we observed 10 galaxies in the MANGROVE catalog (Ducoin et al., 2020) in the 50% region of probability of S250206dm, consistent with the 90% containment volume. We observed between 2025-02-09 02:35 and 06:15 (from T+2.2 to T+2.4 days after the GW transient) and obtained 600 seconds of exposure in r on each galaxy. The data were reduced and stacked using custom software and then calibrated against the PS1 catalog and analysed using STDPipe (Karpov 2021). We carried out image subtraction against PS DR2 images. With one exception, we detect no possible candidates to the 10-sigma limits quoted below: | | Name | RA | Dec | 10-sigma limit | |---|---|---|---|---| | 1 | 2MASS 02242513+5242101 | 36.105 | 52.703 | r > 21.2 | | 2 | 2MASS 02353482+5315284 | 38.895 | 53.258 | r > 20.9 | | 3 | 2MASS 02292273+5329140 | 37.345 | 53.487 | r > 20.2 | | 4 | HyperLEDA 166437 | 40.104 | 54.253 | r > 20.8 | | 5 | 2MASS 02234887+5338542 | 35.954 | 53.648 | r > 20.8 | | 6 | 2MASS 02363571+5351138 | 39.149 | 53.854 | r > 20.6 | | 7 | 2MASS 02363578+5325108 | 39.149 | 53.420 | r > 20.9 | | 8 | 2MASS 02261049+5307282 | 36.544 | 53.125 | r > 19.8 | | 9 | 2MASS 02243083+5251021 | 36.128 | 52.851 | r > 20.7 | | 10 | 2MASS 02371899+5401539 | 39.329 | 54.032 | r > 20.6 | The one exception is that in the field of 2MASS 02363571+5351138 (galaxy 6 above), we detect a transient source 9-3 arcmin from the galaxy at RA = 39.27171 and Dec = 53.99079 degrees with a magnitude of r = 19.98 +/- 0.05. However, a source at the same position appears in the Pan-STARRS catalogs with g = 21.1 in DR1 and at several epochs at g = 22.5 in DR2. We interpret this as a variable star. Our photometry is not corrected for Galactic extinction. We warmly thank the COLIBRÍ and DDRAGO engineering teams and the staff of the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir. View this GCN Circular online at https://gcn.nasa.gov/circulars/39258. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37267] IceCube Alert 250207.09: Global MASTER-Net observations report
by GCN Circulars 09 Feb '25

09 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39257 SUBJECT: IceCube Alert 250207.09: Global MASTER-Net observations report DATE: 25/02/09 20:40:02 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, N.Tiurina, P.Balanutsa, , D.Vlasenko, I.Panchenko, A.Kuznetsov, G.Antipov, A.Sankovich, A.Sosnovskij, Yu.Tselik, M.Gulyaev, Ya.Kechin, V.Senik, A.Chasovnikov, K.Labsina, I. Gorbunov (Lomonosov MSU), O.Gress, N.Budnev (ISU), C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity) D.Buckley (SAAO), R.Rebolo (The Instituto de Astrofisica de Canarias), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory) MASTER-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) started inspect of the IceCube Alert 250207.09 (trigger No 78196104,08h 41m 03.60s , +17d 02m 34.8s, R=4.44) errorbox 14 sec after notice time and 68 sec after trigger time at 2025-02-07 02:09:04 UT, with upper limit up to 19.0 mag. The observations began at zenith distance = 75 deg. The sun altitude is -23.3 deg. MASTER-Tunka robotic telescope located in Russia (Applied Physics Institute, Irkutsk State University) started inspect of the IceCube Alert 250207.09 errorbox 42255 sec after notice time and 42309 sec after trigger time at 2025-02-07 13:53:05 UT, with upper limit up to 19.2 mag. The observations began at zenith distance = 45 deg. The sun altitude is -35.4 deg. The galactic latitude b = 32 deg., longitude l = 209 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2770114 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 74 | 2025-02-07 02:09:04 | MASTER-SAAO | (08h 40m 36.36s , +17d 03m 01.6s) | C | 10 | 17.3 | 94 | 2025-02-07 02:09:04 | MASTER-SAAO | (08h 40m 36.36s , +17d 03m 01.5s) | C | 50 | 18.3 | Coadd 108 | 2025-02-07 02:09:33 | MASTER-SAAO | (08h 40m 36.80s , +17d 03m 02.9s) | C | 20 | 17.9 | 147 | 2025-02-07 02:10:12 | MASTER-SAAO | (08h 40m 37.31s , +17d 03m 04.8s) | C | 20 | 17.8 | 191 | 2025-02-07 02:10:51 | MASTER-SAAO | (08h 40m 37.89s , +17d 03m 06.7s) | C | 30 | 18.0 | 245 | 2025-02-07 02:11:40 | MASTER-SAAO | (08h 40m 38.66s , +17d 03m 09.0s) | C | 40 | 18.1 | 309 | 2025-02-07 02:12:39 | MASTER-SAAO | (08h 40m 39.56s , +17d 03m 11.7s) | C | 50 | 18.1 | 383 | 2025-02-07 02:13:48 | MASTER-SAAO | (08h 40m 40.66s , +17d 03m 14.3s) | C | 60 | 18.1 | 462 | 2025-02-07 02:15:06 | MASTER-SAAO | (08h 40m 41.81s , +17d 03m 17.3s) | C | 60 | 18.1 | 541 | 2025-02-07 02:16:26 | MASTER-SAAO | (08h 40m 43.01s , +17d 03m 20.5s) | C | 60 | 18.0 | 620 | 2025-02-07 02:17:45 | MASTER-SAAO | (08h 40m 44.27s , +17d 03m 23.4s) | C | 60 | 18.0 | 699 | 2025-02-07 02:19:04 | MASTER-SAAO | (08h 40m 45.56s , +17d 03m 26.6s) | C | 60 | 17.9 | 778 | 2025-02-07 02:20:23 | MASTER-SAAO | (08h 40m 46.85s , +17d 03m 29.8s) | C | 60 | 17.9 | 857 | 2025-02-07 02:21:42 | MASTER-SAAO | (08h 40m 48.22s , +17d 03m 32.8s) | C | 60 | 17.9 | 936 | 2025-02-07 02:23:01 | MASTER-SAAO | (08h 40m 49.59s , +17d 03m 36.0s) | C | 60 | 17.8 | 1015 | 2025-02-07 02:24:20 | MASTER-SAAO | (08h 40m 51.02s , +17d 03m 38.9s) | C | 60 | 17.8 | 1094 | 2025-02-07 02:25:39 | MASTER-SAAO | (08h 40m 52.46s , +17d 03m 42.2s) | C | 60 | 17.7 | 1173 | 2025-02-07 02:26:58 | MASTER-SAAO | (08h 40m 53.93s , +17d 03m 45.3s) | C | 60 | 17.7 | 1252 | 2025-02-07 02:28:17 | MASTER-SAAO | (08h 40m 55.47s , +17d 03m 48.3s) | C | 60 | 17.6 | 1332 | 2025-02-07 02:29:36 | MASTER-SAAO | (08h 40m 57.02s , +17d 03m 51.7s) | C | 60 | 17.7 | 1411 | 2025-02-07 02:30:56 | MASTER-SAAO | (08h 40m 58.60s , +17d 03m 55.0s) | C | 60 | 17.6 | 1490 | 2025-02-07 02:32:15 | MASTER-SAAO | (08h 41m 00.22s , +17d 03m 58.3s) | C | 60 | 17.5 | 1569 | 2025-02-07 02:33:34 | MASTER-SAAO | (08h 41m 00.88s , +17d 04m 01.8s) | C | 60 | 18.3 | 1629 | 2025-02-07 02:33:34 | MASTER-SAAO | (08h 41m 00.88s , +17d 04m 01.8s) | C | 180 | 19.0 | Coadd 1649 | 2025-02-07 02:34:54 | MASTER-SAAO | (08h 41m 00.70s , +17d 04m 05.2s) | C | 60 | 18.3 | 1728 | 2025-02-07 02:36:12 | MASTER-SAAO | (08h 41m 00.53s , +17d 04m 08.4s) | C | 60 | 18.3 | 1807 | 2025-02-07 02:37:32 | MASTER-SAAO | (08h 41m 00.30s , +17d 04m 12.2s) | C | 60 | 18.3 | 1867 | 2025-02-07 02:37:32 | MASTER-SAAO | (08h 41m 00.29s , +17d 04m 12.1s) | C | 180 | 18.9 | Coadd 1886 | 2025-02-07 02:38:51 | MASTER-SAAO | (08h 41m 00.06s , +17d 04m 15.9s) | C | 60 | 18.3 | 1965 | 2025-02-07 02:40:10 | MASTER-SAAO | (08h 40m 59.84s , +17d 04m 19.2s) | C | 60 | 18.3 | 2044 | 2025-02-07 02:41:29 | MASTER-SAAO | (08h 40m 59.57s , +17d 04m 23.3s) | C | 60 | 18.2 | 2104 | 2025-02-07 02:41:29 | MASTER-SAAO | (08h 40m 59.56s , +17d 04m 23.4s) | C | 180 | 18.8 | Coadd 2123 | 2025-02-07 02:42:48 | MASTER-SAAO | (08h 40m 59.30s , +17d 04m 27.4s) | C | 60 | 18.2 | 2203 | 2025-02-07 02:44:07 | MASTER-SAAO | (08h 40m 59.02s , +17d 04m 31.8s) | C | 60 | 18.1 | 2281 | 2025-02-07 02:45:26 | MASTER-SAAO | (08h 40m 58.78s , +17d 04m 36.4s) | C | 60 | 18.1 | 2341 | 2025-02-07 02:45:26 | MASTER-SAAO | (08h 40m 58.77s , +17d 04m 36.5s) | C | 180 | 18.7 | Coadd 2361 | 2025-02-07 02:46:45 | MASTER-SAAO | (08h 40m 58.40s , +17d 04m 42.0s) | C | 60 | 18.0 | 2440 | 2025-02-07 02:48:05 | MASTER-SAAO | (08h 40m 58.05s , +17d 04m 47.5s) | C | 60 | 17.9 | 2519 | 2025-02-07 02:49:24 | MASTER-SAAO | (08h 40m 57.72s , +17d 04m 52.7s) | C | 60 | 17.9 | 2579 | 2025-02-07 02:49:24 | MASTER-SAAO | (08h 40m 57.72s , +17d 04m 52.7s) | C | 180 | 18.5 | Coadd 2599 | 2025-02-07 02:50:43 | MASTER-SAAO | (08h 40m 57.35s , +17d 04m 58.0s) | C | 60 | 17.8 | 2678 | 2025-02-07 02:52:03 | MASTER-SAAO | (08h 40m 56.91s , +17d 05m 03.9s) | C | 60 | 17.6 | 2757 | 2025-02-07 02:53:22 | MASTER-SAAO | (08h 40m 56.44s , +17d 05m 10.0s) | C | 60 | 17.4 | 2836 | 2025-02-07 02:54:41 | MASTER-SAAO | (08h 40m 56.01s , +17d 05m 15.8s) | C | 60 | 17.4 | 2915 | 2025-02-07 02:56:00 | MASTER-SAAO | (08h 40m 55.44s , +17d 05m 22.6s) | C | 60 | 16.8 | 2994 | 2025-02-07 02:57:19 | MASTER-SAAO | (08h 40m 54.71s , +17d 05m 32.1s) | C | 60 | 16.1 | 3074 | 2025-02-07 02:58:38 | MASTER-SAAO | (08h 40m 54.23s , +17d 05m 38.1s) | C | 60 | 15.4 | 3153 | 2025-02-07 02:59:57 | MASTER-SAAO | (08h 40m 53.73s , +17d 05m 43.7s) | C | 60 | 15.3 | 3231 | 2025-02-07 03:01:16 | MASTER-SAAO | (08h 40m 53.86s , +17d 05m 46.9s) | C | 60 | 12.1 | 42320 | 2025-02-07 13:53:05 | MASTER-Tunka | (08h 50m 13.23s , +20d 46m 32.3s) | C | 20 | 18.5 | 42340 | 2025-02-07 13:53:05 | MASTER-Tunka | (08h 50m 13.24s , +20d 46m 32.3s) | C | 60 | 19.2 | Coadd 42344 | 2025-02-07 13:53:28 | MASTER-Tunka | (08h 50m 13.23s , +20d 46m 33.0s) | C | 20 | 18.6 | 42367 | 2025-02-07 13:53:52 | MASTER-Tunka | (08h 50m 13.23s , +20d 46m 34.1s) | C | 20 | 18.5 | 42394 | 2025-02-07 13:54:16 | MASTER-Tunka | (08h 50m 13.22s , +20d 46m 35.3s) | C | 25 | 18.5 | 42423 | 2025-02-07 13:54:44 | MASTER-Tunka | (08h 50m 13.22s , +20d 46m 36.3s) | C | 25 | 18.5 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. View this GCN Circular online at https://gcn.nasa.gov/circulars/39257. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37266] LIGO/Virgo/KAGRA S250206dm: Observations from WINTER
by GCN Circulars 09 Feb '25

09 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39256 SUBJECT: LIGO/Virgo/KAGRA S250206dm: Observations from WINTER DATE: 25/02/09 20:04:26 GMT FROM: Viraj Karambelkar at Indian Inst of Tech,Bombay <karambelkarvraj21197(a)gmail.com> Robert Stein (JSI), Viraj Karambelkar (Caltech), Danielle Frostig (CfA), Mansi Kasliwal (Caltech), Nathan Lourie (MIT), Geoffrey Mo (MIT) and Robert Simcoe (MIT) report: We observed the localization region of the S250206dm (GCN 39175, 39231) with the 1.2 sq. degree near-IR WINTER camera on the Palomar 1-m telescope (Lourie et al. 2021, Frostig et al. 2024) in J-band on two nights UTC 2025-02-08 and 2025-02-09. Our observations began at 2025-02-08 04:05 UTC, approximately 30.7 hours after the merger. Our observations covered a total of 23.8 sq. deg. of sky for which reference images were available, corresponding to 37% of the total probability. Of this, 14% was covered at least twice, while 23% was covered once and will be repeated tonight. Our observations reached a median depth of 18 mag AB. The images were processed using the WINTER data reduction pipeline ( https://github.com/winter-telescope/mirar, https://doi.org/10.5281/zenodo.13352565) using images from the UKIRT Hemisphere survey (Dye et al. 2018) as references for image subtraction. We search for WINTER sources with multiple detections, and for any WINTER source with a cross-match in the alert stream of the Zwicky Transient Facility (Bellm et al. 2019). We further remove stellar sources by cross-matching to Gaia, and we are left with no remaining transient candidates. We also cross-match WINTER detections to the position of all 35 sources reported to TNS in the localisation of S250206dm since merger. We find no WINTER detections for any of these transients. Further observations of the GW event are planned over the coming days. With more data, additional analysis can be performed to identify transients in sky regions without archival UKIRT coverage. This includes the area containing the candidate neutrino counterpart reported by IceCube (GCN 39176), for which initial WINTER data has been taken. WINTER (Wide-field INfrared Transient ExploreR) is a partnership between MIT and Caltech, housed at Palomar Observatory, and funded by NSF MRI, NSF AAG, the David and Lucile Packard Foundation, and the MIT Kavli Institute for Astrophysics and Space Research. View this GCN Circular online at https://gcn.nasa.gov/circulars/39256. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37265] GRB 250204B: GRBAlpha detection
by GCN Circulars 09 Feb '25

09 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39255 SUBJECT: GRB 250204B: GRBAlpha detection DATE: 25/02/09 18:25:51 GMT FROM: Michaela Ďuríšková at Masaryk University <505876(a)mail.muni.cz> M. Duriskova, M. Dafcikova, J. Ripa, M. Kolar (Masaryk U.), A. Pal (Konkoly Observatory), N. Werner (Masaryk U.), M. Ohno, H. Takahashi (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), N. Husarikova, F. Munz , M. Topinka, L. Szakszonova, J.-P. Breuer, F. Hroch (Masaryk U.), T. Urbanec, M. Kasal, A. Povalac (Brno U. of Technology), J. Hudec, J. Kapus, M. Frajt (Spacemanic s.r.o), R. Laszlo, M. Koleda (Needronix s.r.o), M. Smelko, P. Hanak, P. Lipovsky (Technical U. of Kosice), G. Galgoczi (Wigner Research Center/Eotvos U.), Y. Uchida, H. Poon, H. Matake (Hiroshima U.), N. Uchida (ISAS/JAXA), T. Bozoki (Eotvos U.), G. Dalya (Eotvos U.), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), G. Friss (Eotvos U.), Y. Fukazawa, K. Hirose (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), K. Kapas (Eotvos U.), L. L. Kiss (Konkoly Observatory), T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), J. Takatsy (Eotvos U.), K. Torigoe (Hiroshima U.), N. Kogiso, M. Yoneyama (Osaka Metropolitan U.), M. Moritaki (U. Tokyo), T. Kano (U. Michigan) -- the GRBAlpha collaboration. The likely long-duration GRB 250204B (Fermi/GBM detection: GCN 39141; AstroSat/CZTI detection: GCN 39142; SVOM/GRM detection: GCN 39163; Konus/Wind detection: GCN 39205; INTEGRAL/SPI-ACS peak detection at 2025-02-04 ~06:41:14 UTC) was observed by the GRBAlpha 1U CubeSat (Pal et al. 2023, A&A, 677, 40; https://ui.adsabs.harvard.edu/abs/2023A%26A...677A..40P/abstract). The detection was confirmed at the peak time 2025-02-04 06:41:13.6 UTC. The T90 duration measured by GRBAlpha is 6.0 s and the overall significance during T90 reaches 9.1 sigma. The light curve obtained by GRBAlpha is available here: https://grbalpha.konkoly.hu/static/share/GRB250204B_GCN.pdf All GRBAlpha detections are listed at: https://monoceros.physics.muni.cz/hea/GRBAlpha/ GRBAlpha, launched on 2021 March 22, is a demonstration mission for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). The detector of GRBAlpha consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~50 keV to ~1000 keV. To increase the duty cycle and the downlink rate, the upgrade of the on-board data acquisition software stack is in progress. The ground segment is also supported by the radio amateur community and it takes advantage of the SatNOGS network for increased data downlink volume. View this GCN Circular online at https://gcn.nasa.gov/circulars/39255. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37264] GRB 250204A: GRBAlpha detection
by GCN Circulars 09 Feb '25

09 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39254 SUBJECT: GRB 250204A: GRBAlpha detection DATE: 25/02/09 18:19:59 GMT FROM: Michaela Ďuríšková at Masaryk University <505876(a)mail.muni.cz> M. Duriskova, M. Dafcikova, J. Ripa, M. Kolar (Masaryk U.), A. Pal (Konkoly Observatory), N. Werner (Masaryk U.), M. Ohno, H. Takahashi (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), N. Husarikova, F. Munz , M. Topinka, L. Szakszonova, J.-P. Breuer, F. Hroch (Masaryk U.), T. Urbanec, M. Kasal, A. Povalac (Brno U. of Technology), J. Hudec, J. Kapus, M. Frajt (Spacemanic s.r.o), R. Laszlo, M. Koleda (Needronix s.r.o), M. Smelko, P. Hanak, P. Lipovsky (Technical U. of Kosice), G. Galgoczi (Wigner Research Center/Eotvos U.), Y. Uchida, H. Poon, H. Matake (Hiroshima U.), N. Uchida (ISAS/JAXA), T. Bozoki (Eotvos U.), G. Dalya (Eotvos U.), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), G. Friss (Eotvos U.), Y. Fukazawa, K. Hirose (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), K. Kapas (Eotvos U.), L. L. Kiss (Konkoly Observatory), T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), J. Takatsy (Eotvos U.), K. Torigoe (Hiroshima U.), N. Kogiso, M. Yoneyama (Osaka Metropolitan U.), M. Moritaki (U. Tokyo), T. Kano (U. Michigan) -- the GRBAlpha collaboration. The long-duration GRB 250204A (Fermi/GBM detection: GCN 39138; INTEGRAL/SPI-ACS peak detection at 2025-02-04 ~07:28:17 UTC) was observed by the GRBAlpha 1U CubeSat (Pal et al. 2023, A&A, 677, 40; https://ui.adsabs.harvard.edu/abs/2023A%26A...677A..40P/abstract). The detection was confirmed at the peak time 2025-02-04 07:28:19.6 UTC. The T90 duration measured by GRBAlpha is 33.5 s and the overall significance during T90 reaches 9.9 sigma. The light curve obtained by GRBAlpha is available here: https://grbalpha.konkoly.hu/static/share/GRB250204A_GCN.pdf All GRBAlpha detections are listed at: https://monoceros.physics.muni.cz/hea/GRBAlpha/ GRBAlpha, launched on 2021 March 22, is a demonstration mission for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). The detector of GRBAlpha consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~50 keV to ~1000 keV. To increase the duty cycle and the downlink rate, the upgrade of the on-board data acquisition software stack is in progress. The ground segment is also supported by the radio amateur community and it takes advantage of the SatNOGS network for increased data downlink volume. View this GCN Circular online at https://gcn.nasa.gov/circulars/39254. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37263] LIGO/Virgo/KAGRA S250206dm & FRB 20250206A: MASTER observations and possible mother galaxy
by GCN Circulars 09 Feb '25

09 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39253 SUBJECT: LIGO/Virgo/KAGRA S250206dm & FRB 20250206A: MASTER observations and possible mother galaxy DATE: 25/02/09 16:42:38 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, A.Kuznetsov, N.Tiurina, P.Balanutsa, I.Panchenko, A.Chasovnikov K.Zhirkov, G.Antipov, A.Sankovich, A.Sosnovskij, Yu.Tselik, Ya.Kechin, V.Senik, V.Topolev (Lomonosov MSU), O.Gress, N.Budnev, O.Ershova (ISU), C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), D.Buckley (SAAO), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity), R.Rebolo (The Instituto de Astrofisica de Canarias), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory) MASTER600-Tunka robotic telescope located near Baykal lake (Applied Physics Institute, ISU, Lipunov, Korniov, Gorbovskoy, Tiurina & Kuznetsov, 2023, Astronomical Robotic Networks and Operative Multichanel Astrophysics, Lomonosov MSU PRESS, 591 pp. https://msupress.com/en/catalogue/books/book/astronomicheskie-robotizirovan…) was pointed to the FRB 20250206A error box (CHIME team, GCN 39216) 2.4 day after trigger time at 2025-02-08 11:37:22 (57.5h) at 2025-01-29 15:55:03 UT, with upper limit up to 19.4 mag on large zenit distance (80 degrees) and low temperature (<-30C degrees). These observations were made like BOOTES-5 and 2.2m CAHA (A. J. Castro-Tirado et al., GCN 39247) in the background of the LIGO/Virgo/KAGRA S250206dm Grande campaign under Moon, which you can follow in our Web reports, with a detailed report coming soon. Real time updated cover map and discovered OT are available here: https://master.sai.msu.ru/site/master2/ligo_1.php?id=27337 The nearest bright galaxy is the spiral galaxy PGC1403722 (22h 34m 50.64s +12d 05m 46.7s) and could be a candidate host galaxy for the NS+BH pair that ejected from it several billion years ago (GCN 39220) with velocity several 100km/s (see the MASTER image http://observ.pereplet.ru/images/MASTER_FRB20250206A.jpg ). Its distance to Earth is well within the limits of CHIME and LVK S250206dm events. The deep image is welcome. View this GCN Circular online at https://gcn.nasa.gov/circulars/39253. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37262] LIGO/Virgo/KAGRA S250206dm: Optical observations of candidate AT 2025bbo with Kinder
by GCN Circulars 09 Feb '25

09 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39252 SUBJECT: LIGO/Virgo/KAGRA S250206dm: Optical observations of candidate AT 2025bbo with Kinder DATE: 25/02/09 15:09:44 GMT FROM: Janet Chen at National Central University <janetstars(a)gmail.com> Y.-H. Lee, A. Aryan, T.-W. Chen, W.-J. Hou, H.-Y. Hsiao (all NCU), S. J. Smartt (Oxford/QUB), A. K. H. Kong (NTHU), J. Gillanders (Oxford), A. Sankar. K, Y.-C. Pan, C.-C. Ngeow, M.-H. Lee, Y. J. Yang, C.-H. Lai, C.-S. Lin, H.-C. Lin, J.-K. Guo (all NCU), S. Yang, Z. N. Wang, L. L. Fan, G. H. Sun (all HNAS), H.-W. Lin (UMich), H. F. Stevance, S. Srivastav, L. Rhodes (all Oxford), M. Nicholl, M. Fulton, T. Moore, K. W. Smith, C. Angus, A. Aamer (all QUB), A. Schultz and M. Huber (both IfA, Hawaii) report: We observed the field of the optical transient AT 2025bbo (Smartt et al., GCN 39244) in the skymap of the NSBH merger event S250206dm (The LIGO-Virgo-Kagra Collaboration, GCN 39175) from the Pan-STARRS search described in Young et al. (GCN 39210). We used the 1m-LOT at Lulin observatory in Taiwan as part of the Kinder collaboration (Chen & Yang et al., 2024arXiv240609270C). The first epoch of 1m-LOT observations started at 11:06:23 UTC on 9th of February 2025. We employed the Python-based package AutoPhOT (Brennan & Fraser, 2022, A&A, 667, A62) to perform the template subtraction using "sfft" (Hu, 2022, ApJ, 936, 157). We utilized the template image from PanSTARRS1 (Chambers et al. 2016 arXiv:1612.05560). In the difference image, we see a clear signature of the transient. We further utilized the AutoPhOT package to perform PSF photometry. The details of the observations and measured PSF magnitude from the differenced image (in the AB system) of AT 2025bbo are as follows: Telescope | Filter | MJD | Exposure | Magnitude | avg. Seeing | med. Airmass LOT | r | 60715.463 | 300 sec * 6 | 20.08 +/- 0.05 | 1".61 | 1.39 The presented magnitudes are calibrated using the field stars from the Pan-STARRS1 catalog and are not corrected for the expected Galactic foreground extinction corresponding to a reddening of A_r = 0.24 mag in the direction of the burst (Schlafly & Finkbeiner 2011). Our photometry indicates that AT 2025bbo is brightening at a rate of approximately 0.3 mag per day, compared to the measurements reported by Smartt et al. (GCN 39244) and Liu et al. (GCN 39249). View this GCN Circular online at https://gcn.nasa.gov/circulars/39252. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37261] Fermi-LAT Gamma-ray Observations of IceCube-250207A
by GCN Circulars 09 Feb '25

09 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39251 SUBJECT: Fermi-LAT Gamma-ray Observations of IceCube-250207A DATE: 25/02/09 14:45:10 GMT FROM: Simone Garrappa at Weizmann Institute of Science <simone.garrappa(a)weizmann.ac.il> S. Garrappa (Weizmann Institute of Science), L. Pfeiffer (Univ. of Wuerzburg), C. Bartolini (INFN Bari), S. Buson (DESY, Univ. of Wuerzburg) and P. M. Veres (Ruhr University Bochum) on behalf of the Fermi-LAT collaboration: We report an analysis of observations of the vicinity of the high-energy IC250207A neutrino event (GCN 39203) with all-sky survey data from the Large Area Telescope (LAT), on board the Fermi Gamma-ray Space Telescope. The IceCube event was detected on 2025-02-07 02:07:55.27 UTC (T0) with J2000 position RA = 132.93 (+2.05, -1.89) deg, Decl. = 20.66 (+1.28, -1.40) deg 90% PSF containment. Two cataloged gamma-ray sources are found within the 90% IC250207A localization error (The Fourth Fermi-LAT catalog, 4FGL-DR4, The Fermi-LAT collaboration 2023, arXiv:2307.12546). These are 4FGL J0854.8+2006 (associated with the FSRQ OJ 287) and 4FGL J0856.8+2056 (associated with the FSRQ TXS 0853+211) at 0.9 deg and 1.2 deg from the best-fit neutrino position, respectively. Based on a preliminary analysis of the LAT data over the timescales of 1-day and 1-month before T0, these objects are not significantly detected at gamma-rays. We searched for the existence of intermediate (days to years) timescale emission from a new gamma-ray transient source. Preliminary analysis indicates no significant (>5sigma) new excess emission (> 100 MeV) within the IC250207A 90% confidence localization. Assuming a power-law spectrum (photon index = 2.0 fixed) for a point source at the IceCube best-fit position, the >100 MeV flux upper limit (95% confidence) is <2.4e-10 ph cm^-2 s^-1 for ~16-years (2008-08-04 / T0), <6.9e-09(<5.6e-8) ph cm^-2 s^-1 for a 1-month (1-day) integration time before T0. Since Fermi normally operates in an all-sky scanning mode, regular monitoring of this source will continue. For this source, the Fermi-LAT contact person is S. Garrappa (simone.garrappa at weizmann.ac.il). The Fermi LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden. View this GCN Circular online at https://gcn.nasa.gov/circulars/39251. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37260] GRB 250207A: 1.3m DFOT Optical observations
by GCN Circulars 09 Feb '25

09 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39250 SUBJECT: GRB 250207A: 1.3m DFOT Optical observations DATE: 25/02/09 14:25:06 GMT FROM: Amit Kumar Ror at ARIES <mitturor77894(a)gmail.com> Amit K. Ror, Anshika Gupta, Kiran, Shashi B. Pandey, Kuntal Mishra (ARIES) report: We observed the field of GRB 250207A detected by the Swift Burst Alert Telescope (Swift team, Ferro et al. 2025; GCN 39182) with the 1.3m Devasthal Fast Optical Telescope (DFOT), located at the Devasthal Observatory of the Aryabhatta Research Institute of Observational Sciences (ARIES), India. The observations were started on 2025-02-07 at 13:41:42 UT, i.e., ~ 0.52 days after the Swift-BAT trigger. We have taken multiple frames with an exposure time of 300 s in the R filter. We stacked the images after the alignment. We detected an optical afterglow in our stacked image within the error box of the enhanced Swift-XRT position by Osborne et al. 2025 (GCN 39217). We obtain the following preliminary magnitude in the stacked image: Date Start_UT T_start-T0 (days) Filter Exp time (s) Magnitude ========================================================= 2025-02-07 13:41:42 ~0.52 R 300s*4 21.12 +/- 0.15 Our detection is consistent with Angulo et al. 2025 (GCN 39186); Kuin et al. 2025 (GCN 39199); Brivio et al. 2025 (GCN 39202); Jelinek et al. 2025 (GCN 39209) and Ferro et al. 2025 (GCN 39212). The magnitude is not corrected for the Galactic extinction in the direction of the burst. Photometric calibration is performed using the standard stars from the USNO-B1.0 catalogue. This circular may be cited. View this GCN Circular online at https://gcn.nasa.gov/circulars/39250. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37259] LIGO/Virgo/KAGRA S250206dm: WFST follow-up observations
by GCN Circulars 09 Feb '25

09 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39249 SUBJECT: LIGO/Virgo/KAGRA S250206dm: WFST follow-up observations DATE: 25/02/09 14:02:04 GMT FROM: Zhengyan Liu at USTC <ustclzy(a)mail.ustc.edu.cn> Z. Y. Liu, L. He, W. Zhao, J.-A. Jiang, Z. L. Xu, D. Z. Meng, Z. Y. Cai, M. X. Cai, T. G. Wang, X. Kong, Z. G. Dai, L. L. Fan (USTC), Z. P. Jin, X. F. Wu (PMO) report on behalf of the WFST Collaboration: Following the detection of the gravitational wave event S250206dm (the LIGO-Virgo-Kagra Collaboration, GCN 39175), we conducted follow-up observations at the high-probability region using the newly deployed Wide Field Survey Telescope (WFST Collaboration; Wang et al., 2023) at Lenghu Astronomical Observation Base (Qinghai province, China) from 2025-02-07T12:10:00 to 2025-02-07T17:00:04 UTC and 2025-02-08T12:14:53 to 2025-02-08T17:14:15 UTC, corresponding to 14.74 and 38.82 hours after the merger event (UTC 2025-02-06T21:25:30.44), respectively. We observed in WFST r, i, and z bands with exposure time of 60-90 seconds. A total area of about 333 square degrees of the 90% area in the Bilby.fits skymap (GCN 39231) was observed, covering 64% of the event localization. We checked WFST data for the previously reported transient candidates AT2025azm, AT2025azn, and AT2025bbo (GCN 39191; GCN 39244). Our targeted observations include 90s exposures in r and i bands for AT2025azm, 60s exposures in r, i, and z bands for AT2025azn, and 60s exposures in r and i bands for AT2025bbo. Observations of AT2025azm began at 2025-02-07T12:30:01 UTC, 15.08 hours post-merger; AT2025azn was observed starting at 2025-02-07T14:38:44 UTC, 17.21 hours post-merger; and AT2025bbo was observed starting at 2025-02-07T13:50:35 UTC, 16.42 hours post-merger. All images were processed with the WFST pipeline. After astrometric and photometric calibration, image subtraction was performed using templates of the PS1 stacked images (Waters et al., 2020). For AT2025azm and AT2025azn, we did not detect any transient in observed bands. The observations were carried out under seeing conditions of 0.9-1.3 arcseconds during the first night (starting at 2025-02-07T12:10:00 UTC). The 5-sigma non-detection limits for the two objects are as follows: AT2025azm: r > 22.2, i > 21.8; AT2025azn: r > 21.7, i > 21.4, z > 20.5. For AT2025bbo, we detected the transient in both r and i bands on the first night. However, the target was not found on the second night due to cloudy weather. The 1st-night photometric results for AT2025bbo are: r = 20.5 +/- 0.1, i = 20.3 +/- 0.1. In addition, the r-band magnitude reported by Pan-STARRS (GCN 39244) is r = 20.45 +/- 0.2 and the time interval between our observations is ~0.7 day, suggesting a slow evolution for AT2025bbo. Subsequent WFST observations and a systematic search of potential transients are ongoing. View this GCN Circular online at https://gcn.nasa.gov/circulars/39249. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37258] GRB 250206A: Swift-XRT observations
by GCN Circulars 09 Feb '25

09 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39248 SUBJECT: GRB 250206A: Swift-XRT observations DATE: 25/02/09 11:57:12 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> T. Sbarrato (INAF-OAB), M. A. Williams (PSU), S. Dichiara (PSU), J.A. Kennea (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), P. D'Avanzo (INAF-OAB), M.G. Bernardini (INAF-OAB) and P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team: Swift-XRT has performed follow-up observations of the Fermi/LAT-detected burst GRB 250206A in a series of observations tiled on the sky. The total exposure time is 4.3 ks, distributed over 10 tiles; the maximum exposure at a single sky location in the tiling was 978 s. The data were collected between T0+162.0 ks and T0+179.3 ks, and are entirely in Photon Counting (PC) mode. Three uncatalogued X-ray sources have been detected, however none of them is above the RASS limit or shows definitive signs of fading. Therefore, at the present time we cannot identify which, if any, is the afterglow. Details of these sources are given below: Source 1: RA (J2000.0): 224.6223 = 14:58:29.34 Dec (J2000.0): -62.7146 = -62:42:52.5 Error: 8.2 arcsec (radius, 90% conf.) Count-rate: 0.0205 [+0.0125, -0.0089] ct s^-1 Distance: 1996 arcsec from Fermi/LAT position. Source 3: RA (J2000.0): 225.3635 = 15:01:27.23 Dec (J2000.0): -62.3210 = -62:19:15.4 Error: 17.4 arcsec (radius, 90% conf.) Count-rate: (7.8 [+5.0, -3.6])e-3 ct s^-1 Distance: 236 arcsec from Fermi/LAT position. Source 4: RA (J2000.0): 225.7331 = 15:02:55.95 Dec (J2000.0): -62.5032 = -62:30:11.4 Error: 8.8 arcsec (radius, 90% conf.) Count-rate: (9.0 [+5.1, -3.7])e-3 ct s^-1 Distance: 1124 arcsec from Fermi/LAT position. A catalogued source was also detected. The results of the XRT-team automatic analysis of the tiled XRT observations, including a position-specific upper limit calculator, are available at https://www.swift.ac.uk/xrt_products/TILED_GRB00132. This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/39248. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37257] LIGO/Virgo/KAGRA S250206dm: FRB 20250206A BOOTES-5 and 2.2m CAHA optical upper limits
by GCN Circulars 09 Feb '25

09 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39247 SUBJECT: LIGO/Virgo/KAGRA S250206dm: FRB 20250206A BOOTES-5 and 2.2m CAHA optical upper limits DATE: 25/02/09 08:48:42 GMT FROM: Alberto Castro-Tirado at Inst.de Astro. de Andalucia <ajct(a)iaa.es> A. J. Castro-Tirado, I. Perez-Garcia, M. D. Caballero-Garcia, E. Fernandez-Garcia, S. Guziy, R. Sanchez-Ramirez and S.-Y. Wu (IAA-CSIC), A. Sintes (Univ. Illes Balears), J. A. Font (Univ. de Valencia), Y.-D. Hu (GXU), M. Gritsevich (Univ. of Helsinki), G. Garcia-Segura, and D. Hiriart (Instituto de Astronomía-UNAM, Ensenada), W. H. Lee (UNAM) and I. Hermelo (CAHA), on behalf of a larger collaboration, report: Following the detection of the compact binary merger (either NS-NS or NS-BH) event S250206dm (the LIGO-Virgo-Kagra Collaboration, GCNC 39175) and the report of a near simultaneous fast radio burst (dubbed FRB 20250206A, the CHIME/FRB collaboration, GCNC 39216), we conducted follow-up optical observations on Feb 8 with both the 0.6m J. Gorosabel robotic telescope at the BOOTES-5 station in Observatorio Nacional de San Pedro Martir (Mexico) and the 2.2m telescope at Calar Alto Observatory (Spain). Data were gathered under poor conditions, due to the extremely high airmass of the target (larger than 4), resulting in null optical detection at the position of FRB 20250206A, with the upper limits for the unfiltered images being 16.5 (2:30 UT) and 20.1 (19:00 UT) respectively. If the two events would be related, the absence of an optical transient similar to AT 2017gfo (associated to GW 170817A) would be explained by the larger distance (373+/-104 Mpc, LKV collaboration, GCNC 39231) compared to 40 Mpc (for AT 2017gfo in NGC 4993). The absence of a host galaxy in archival PanSTARRS1 images would be also in agreement with Lipunov et al.’s suggestion (GCNC 39220). View this GCN Circular online at https://gcn.nasa.gov/circulars/39247. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37256] GRB 250129A: GRANDMA Continued Afterglow Detection
by GCN Circulars 09 Feb '25

09 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39246 SUBJECT: GRB 250129A: GRANDMA Continued Afterglow Detection DATE: 25/02/09 07:57:22 GMT FROM: Sarah Antier at OCA <sarah.antier(a)oca.eu> D. Akl (AUS), S. Antier (OCA/IJCLAB), M. Tanasan (NARIT). A. Simon (TShNU of Kyiv), N. Sasaki (OPD/LNA), S. Karpov (FZU), D. Turpin (CEA-Saclay/Irfu), M. Coughlin (UMN), P. Hello (IJCLAB), C. Andrade (UMN), P-A Duverne (APC), T. Pradier (Unistra/IPHC), I. Tosta e Melo (UniCT-DFA), N. Guessoum (AUS), A. Takey (NRIAG), Y. Hendy (NRIAG), M. Abdelkareem (NRIAG), E. Elhosseiny (NRIAG), N. Kochiashvili (AbAO), V. Zhuzhunadze (AbAO), V.Aivazyan (AbAO), R. Inasaridze (AbAO), A. Klotz (IRAP), F. Colas (Obs-Paris/LTE), A. Iskandar（XAO), X. F. Wang (THU), R. Hellot, M. Freeberg, S. Leonini, C. Galdies (KNC), B. M. Mihov (BAS), L. Slavcheva-Mihova (BAS), T. Sun (PMO), F. Dux (Euler), on behalf of GRANDMA: We observed the field of GRB 250129A detected by Swift (Beardmore et al., GCN 39066) using GRANDMA and its citizen science project Kilonova-catcher (KNC). We clearly detect the optical afterglow and we report a subset of the following magnitudes using different instruments: | T-T0 (d)|Filter| Magnitude (AB) |Exposure(s)| Telescope | | 0.65 | g' | 19.21 +/- 0.03 | 10x100s | TNOT | | 0.86 | i' | 18.92 +/- 0.03 | 5x150s | KAO | | 2.77 | R | 20.19 +/- 0.08 | 50x60s | AbAO-T70 | | 3.04 | V | 20.35 +/- 0.04 | 3x600s | KNC | | 4.88 | g' | 21.12 +/- 0.06 | 10x600s | NAO-2m | | 6.99 | r' | 22.8 +/- 0.14 | 20x180s | 1m-PicduMidi | All the data have been reduced by a single data processing pipeline, STDPipe (Karpov et al., 2022). Images obtained in Johnson Cousin filters were calibrated using the Gaia DR3 Synphot catalog, images taken with Sloan filters were calibrated with PanSTARRS-DR1 Catalog. Our measurements are not corrected from extinction. Weather conditions were excellent in all sites. We use the SkyPortal application (skyportal.io) to monitor our observational campaign (Coughlin et al. 2023). GRANDMA is a worldwide telescope network (grandma.ijclab.in2p3.fr) devoted to the observation of transients in the context of multi-messenger astrophysics (Antier et al. 2020 MNRAS 497, 5518). Kilonova-Catcher (KNC) is the citizen science program of GRANDMA (http://kilonovacatcher.in2p3.fr/). View this GCN Circular online at https://gcn.nasa.gov/circulars/39246. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37255] GRB 250207A: Swift-BAT refined analysis
by GCN Circulars 09 Feb '25

09 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39245 SUBJECT: GRB 250207A: Swift-BAT refined analysis DATE: 25/02/09 00:53:00 GMT FROM: Rahul Gupta at NASA GSFC <rahul.gupta(a)nasa.gov> M. J. Moss (GSFC), S. D. Barthelmy (GSFC), M. Ferro (INAF-OAB), R. Gupta (GSFC), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Parsotan (GSFC), D. Sadaula (GSFC/UMBC), T. Sakamoto (AGU) (i.e. the Swift-BAT team): Using the data set from T-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 250207A (trigger #1287821) (Ferro, et al., GCN Circ. 39182). The BAT ground-calculated position is RA, Dec = 16.097, -12.165 deg which is RA(J2000) = 01h 04m 23.4s Dec(J2000) = -12d 09' 55.0" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 72%. The masked weighted BAT light curve shows a prominent multi-peaked structure, with the most significant activity occurring within the first 50 seconds after the trigger. T90 (15-350 keV) is 52.54 +- 19.87 sec (estimated error including systematics). The time-averaged spectrum from T-6.60 to T+100.22 sec is the best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.27 +- 0.08. The fluence in the 15-150 keV band is 3.7 +- 0.2 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from T+7.01 sec in the 15-150 keV band is 2.6 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at https://swift.gsfc.nasa.gov/results/batgrbcat/BAT_refined_circular/1287821 View this GCN Circular online at https://gcn.nasa.gov/circulars/39245. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37254] LIGO/Virgo/KAGRA S250206dm: further Pan-STARRS observations and one candidate AT2025bbo
by GCN Circulars 09 Feb '25

09 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39244 SUBJECT: LIGO/Virgo/KAGRA S250206dm: further Pan-STARRS observations and one candidate AT2025bbo DATE: 25/02/09 00:03:13 GMT FROM: Stephen Smartt at University of Oxford <s.smartt(a)qub.ac.uk> S. J. Smartt (Oxford/QUB), M. E. Huber (IfA, Hawaii), K. W. Smith (Oxford/QUB), S. Srivastav(Oxford), D. R. Young (QUB), J. H. Gillanders (Oxford), K. C. Chambers (IfA, Hawaii), F. Stoppa (Oxford), M. Nicholl, M. D. Fulton, M. McCollum, T. Moore, S. Sim, J. Weston, A. Aamer, C. R. Angus, X. Sheng (QUB), P. Ramsden (QUB/Birmingham), L. Shingles (GSI/QUB), H. Stevance,(Oxford), L. Rhodes (TSI/McGill), A. S. B. Schultz, T. de Boer, J. Fairlamb, H. Gao, C. C. Lin, T. Lowe, E. Magnier, P. Minguez, G. Paek, A. Smith, R. J. Wainscoat (IfA, Univ. Hawaii), T.-W. Chen (NCU), A. Rest (STScI), C. Stubbs (Harvard) Further to the Pan-STARRS coverage of the NSBH merger event S250206dm (The LIGO-Virgo-Kagra Collaboration, GCN 39175) described in Young et al. GCN 39210, we report updates from observations with the the Pan-STARRS telescope system (Chambers et al., 2016, ArXiv e-prints, 1612.05560). We observed the skymap on a second night, again with individual r-band images of 45 seconds. The first and second night images were stacked and difference imaging was again run. We have covered 50% of the new, updated map of GCN 39231 (Bilby.offline1.multiorder.fits,0 ; LIGO-Virgo-Kagra Collaboration). We filter out candidates which have previous detections in Pan-STARRS, ZTF (Lasair Broker database) or ATLAS or are stars/compact galaxies with activity. In the new, much smaller skymap, we are left with only one possible candidate. AT2025bbo : 01:37:17.27 +45:43:31.8. r = 20.45 +/- 0.2 The transient is 0.20" S, 0.26" W from the galaxy centre, SDSS J013717.29+454331.8. SDSS DR15 Photoz z = 0.079 +/- 0.0207 and photoz = 0.0657 from NED (source 2MASS phometric redshift survey). Non-detection 60713.3, and detected at r = 20.45 +/- 0.2 a day later on 60714.3. This implies M_r = -17.6 +/- 0.7 (accounting for foreground Milky Way extinction). The photometric redshift is compatible with the LVK estimate of the GW distance, but it is somewhat luminous for a kilonova. We checked the ATLAS forced photometry server (Shingles et al. AstroNote 2021-7, Smith et al., 2020, PASP, 132, 1) and the Pan-STARRS all-sky database and neither show activity before the time of S250206dm. We caution that the excess could still be nuclear activity, or subtraction residuals and further data should elucidate. Other surveys should check for pre-GW flux excesses. The coordinates and further details of AT2025bbo and other sources detected in our skymap are available on the IAU Transient Name server page for s250206dm : https://www.wis-tns.org/ligo/o4/S250206dm_20250206_212530 View this GCN Circular online at https://gcn.nasa.gov/circulars/39244. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37253] LIGO/Virgo/KAGRA S250207bg: Updated NED Galaxies in the Localization Volume
by GCN Circulars 08 Feb '25

08 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39243 SUBJECT: LIGO/Virgo/KAGRA S250207bg: Updated NED Galaxies in the Localization Volume DATE: 25/02/08 21:48:25 GMT FROM: David Cook at Caltech/IPAC-NED <dcook(a)ipac.caltech.edu> David O. Cook (Caltech/IPAC), Rick Ebert (Caltech/IPAC), George Helou (Caltech/IPAC), Joseph M. Mazzarella (Caltech/IPAC), Marion Schmitz (Caltech/IPAC), and Leo Singer (NASA/GSFC) On behalf of the NASA/IPAC Extragalactic Database (NED) Team. We spatially cross-matched the LVK S250207bg-4-Update sky localization with the NED Local Volume Sample (NED-LVS; Cook et al. 2023), which is a subset of NED with a redshift or redshift-independent distance less than 1000 Mpc. We find 5657 galaxies within the 90% containment volume, and we list here the top 20 galaxies sorted by the joint probability of the 3D localization and the WISE W1 luminosity (an observable proxy for stellar mass). For the full or top 20 list of galaxies in the 90% volume go either to the NED Gravitational Wave Followup service at https://ned.ipac.caltech.edu/uri/NED::GWF/ or click on the following links: Full List Download: https://ned.ipac.caltech.edu/uri/NED::GWFglist/fits/S250207bg/4 Top 20 List Download: https://ned.ipac.caltech.edu/uri/NED::GWFglist/fits/S250207bg/4/20 The NED-GWF service provides downloadable galaxy lists and visualizations for candidate host galaxies. For each GW alert, these products are automatically generated and made available within minutes to expedite efficient electromagnetic follow-up observations. The NED top 20 list is sorted by the joint probability of the 3D localization and the WISE W1 luminosity, but users can sort on additional pre-computed prioritization metrics (star formation rate, P_3D * P_SFR; and specific star formation rate, P_3D * P_sSFR; etc.) which are available via downloading the entire galaxy list inside the event's probability volume. | objname| ra| dec|objtype| DistMpc|DistMpc_unc| m_NUV| m_NUV_unc| m_Ks| m_Ks_unc| m_W1| m_W1_unc| P_3D|P_3D_LumW1| |-------------------------|--------------|--------------|-------|-----------|-----------|------------|------------|------------|------------|------------|------------|--------|----------| |WISEA J154012.34+184306.0| 235.05140| 18.71817| G| 417.30| 0.08| null| null| 13.309| 0.160| 9.114| 0.005|4.63e-07| 4.25e-09| |WISEA J153919.63+190427.7| 234.83187| 19.07453| G| 530.26| null| null| null| 13.627| 0.172| 10.078| 0.006|6.58e-07| 4.02e-09| |WISEA J150631.38+283419.0| 226.63079| 28.57192| G| 515.26| 0.04| null| null| 13.286| 0.172| 10.718| 0.006|1.05e-06| 3.33e-09| |WISEA J152319.42+240611.6| 230.83105| 24.10320| G| 663.87| 0.16| null| null| 14.431| 0.157| 10.454| 0.006|3.02e-07| 2.04e-09| |WISEA J153645.35+185715.6| 234.18906| 18.95426| G| 614.30| 0.14| null| null| 14.462| 0.165| 11.145| 0.006|6.22e-07| 1.90e-09| |WISEA J155856.52+032444.3| 239.73542| 3.41238| G| 408.76| 0.10| null| null| 12.955| 0.169| 10.037| 0.006|4.26e-07| 1.63e-09| |WISEA J155910.92+030431.4| 239.79539| 3.07516| G| 280.12| 0.10| 21.046| 0.115| 13.699| 0.080| 8.330| 0.005|1.72e-07| 1.49e-09| |WISEA J151550.70+275958.5| 228.96137| 27.99951| G| 504.04| 0.05| 20.968| 0.139| 13.749| 0.153| 10.538| 0.006|3.97e-07| 1.43e-09| |WISEA J154844.37+123355.8| 237.18490| 12.56552| G| 445.05| 0.19| 18.149| 0.040| 12.533| 0.102| 11.704| 0.007|1.20e-06| 1.15e-09| |WISEA J155025.85+130154.2| 237.60767| 13.03173| G| 581.25| 0.10| null| null| 13.459| 0.155| 10.806| 0.006|2.99e-07| 1.12e-09| |WISEA J151458.01+273639.7| 228.74172| 27.61105| G| 560.27| 0.21| 22.052| 0.306| 11.568| 0.117| 11.617| 0.007|6.75e-07| 1.11e-09| |WISEA J150746.48+284911.8| 226.94359| 28.81997| G| 515.60| 0.75| 20.018| 0.182| 12.395| 0.100| 12.063| 0.007|1.16e-06| 1.07e-09| |WISEA J154015.93+175229.2| 235.06642| 17.87478| G| 474.23| null| null| null| 12.689| 0.157| 11.861| 0.007|1.13e-06| 1.06e-09| |WISEA J151503.66+265734.0| 228.76522| 26.95947| G| 507.59| 0.10| 20.870| 0.165| 12.543| 0.112| 12.330| 0.009|1.31e-06| 9.22e-10| |WISEA J155420.39+092929.4| 238.58486| 9.49159| G| 479.41| 0.09| null| null| 12.282| 0.120| 12.132| 0.010|1.22e-06| 9.19e-10| | [HB89] 1552+085| 238.68574| 8.37263| QSO| 557.07| 0.06| 17.225| 0.024| 12.724| 0.045| 11.383| 0.023|4.08e-07| 8.25e-10| |WISEA J153844.73+174212.6| 234.68642| 17.70348| G| 436.35| 0.22| 17.650| 0.046| 12.354| 0.105| 11.900| 0.007|1.06e-06| 8.19e-10| |WISEA J152816.73+224844.1| 232.06975| 22.81227| G| 469.92| 0.17| null| null| 12.642| 0.095| 12.342| 0.007|1.33e-06| 7.95e-10| |WISEA J153116.63+220554.7| 232.81929| 22.09851| G| 456.31| 0.21| null| null| 12.372| 0.077| 11.994| 0.008|9.92e-07| 7.69e-10| | 3C 327| 240.61406| 1.96560| G| 486.72| 2.15| 20.654| 0.174| 12.897| 0.047| 11.037| 0.006|3.51e-07| 7.51e-10| Table 1: Top 20 galaxies in NED-LVS that fall in the 90% probability volume for S250207bg sorted by the joint probability of 3D position and WISE W1 luminosity (P_3D * P_LumW1). Galaxy is the NED preferred name. RA and Dec are the Equatorial coordinates in degrees (J2000). Objtype is the object type of the galaxy candidate. Distance is the distance to the galaxy in Mpc. m_NUV and mErr_NUV are the apparent magnitude and error from GALEX. m_Ks and mErr_Ks are the apparent magnitude and error from 2MASS. m_W1 and mErr_W1 are the apparent magnitude and error from AllWISE. P_3D is the probability that the galaxy is in the volume given the distance of GW event. P_3D_LumW1 is the joint probability within the volume weighted by the WISE1 luminosity of the galaxy (P_3D * P_LumW1). View this GCN Circular online at https://gcn.nasa.gov/circulars/39243. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37252] LIGO/Virgo/KAGRA S250207bg: Updated Sky localization
by GCN Circulars 08 Feb '25

08 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39242 SUBJECT: LIGO/Virgo/KAGRA S250207bg: Updated Sky localization DATE: 25/02/08 20:47:18 GMT FROM: Will Farr <will.farr(a)stonybrook.edu> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Livingston Observatory (L1) and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S250207bg (GCN Circular 39201). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S250207bg For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 80 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 508 +/- 95 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380 View this GCN Circular online at https://gcn.nasa.gov/circulars/39242. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37251] LIGO/Virgo/KAGRA S250206dm: GECKO coverage of S240206dm
by GCN Circulars 08 Feb '25

08 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39241 SUBJECT: LIGO/Virgo/KAGRA S250206dm: GECKO coverage of S240206dm DATE: 25/02/08 18:05:24 GMT FROM: Gregory Paek at Seoul National University <gregorypaek94(a)gmail.com> Gregory S.H. Paek (IfA), Myungshin Im, Mankeun Jeong, Hyeonho Choi, Seo-Won Chang, Ji Hoon Kim, Donggeun Tak, Hongjae Moon (SNU/SNU ARC), Dong-Jin Kim and Chung-Uk Lee (KASI), on behalf of the GECKO team We report ongoing follow-up observations of the LIGO/Virgo/Kagra (LVK) gravitational-wave (GW) event, S250206dm (LVK Collaboration, GCN 39175) with the 7-Dimensional Telescope (7DT) and Korean Microlensing Telescope Network (KMTNet) located in the Southern Hemisphere. The KMTNet is a system made of three 1.6-meter class telescopes each at SAAO in South Africa, CTIO in Chile, and SSO in Australia. The KMTNet field of view of a single pointing covers a ~2 deg by 2 deg area. The KMTNet observation started on 2025-02-07 02:17 (UT) or about 4.86 hrs after the GW event, and we took a series of R-band images with exposure times ranging from 2*120 sec to 5*120 sec per pre-defined tiles covering regions that overlapped with the 90% credible area of GW skymap. As a result, we covered 57 tiles (~220 deg^2) within the area. ------ RA DEC SITE FILTER EXPTIME[s] DATE-OBS[UT] 11:15:00 -46:00:00 CTIO R 480 2025-02-07 2:17:05 10:22:01 -26:48:31 CTIO R 480 2025-02-07 4:36:16 10:22:01 -26:48:31 CTIO R 480 2025-02-07 4:36:16 11:03:45 -46:00:00 CTIO R 480 2025-02-07 5:05:31 11:05:27 -44:00:00 CTIO R 600 2025-02-07 5:32:00 11:19:01 -48:00:00 CTIO R 480 2025-02-07 6:04:04 11:19:01 -48:00:00 CTIO R 480 2025-02-07 6:04:04 11:29:45 -50:00:00 CTIO R 480 2025-02-07 6:33:03 11:29:45 -50:00:00 CTIO R 480 2025-02-07 6:33:03 10:24:35 -28:43:24 CTIO R 480 2025-02-07 6:45:32 10:24:35 -28:43:24 CTIO R 480 2025-02-07 6:45:32 11:16:22 -44:00:00 CTIO R 480 2025-02-07 6:58:06 11:34:44 -52:00:00 CTIO R 480 2025-02-07 7:10:18 11:34:44 -52:00:00 CTIO R 480 2025-02-07 7:10:18 10:48:00 -40:00:00 CTIO R 480 2025-02-07 7:22:12 11:07:19 -48:00:00 CTIO R 600 2025-02-07 7:34:15 11:07:19 -48:00:00 CTIO R 600 2025-02-07 7:34:15 10:38:56 -34:00:00 CTIO R 480 2025-02-07 7:46:21 10:06:44 -19:08:56 CTIO R 480 2025-02-07 8:01:04 10:06:44 -19:08:56 CTIO R 480 2025-02-07 8:01:04 11:30:44 -48:00:00 CTIO R 480 2025-02-07 8:13:12 11:30:44 -48:00:00 CTIO R 480 2025-02-07 8:13:12 10:19:32 -24:53:37 CTIO R 480 2025-02-07 8:25:08 10:19:32 -24:53:37 CTIO R 480 2025-02-07 8:25:08 10:00:00 -17:14:03 CTIO R 480 2025-02-07 8:52:10 10:00:00 -17:14:03 CTIO R 480 2025-02-07 8:52:10 10:13:38 -21:03:50 CTIO R 480 2025-02-07 9:16:28 10:13:38 -21:03:50 CTIO R 480 2025-02-07 9:16:28 10:50:00 -38:00:00 CTIO R 240 2025-02-07 9:28:34 09:58:39 -19:08:56 SAAO R 480 2025-02-07 19:08:01 09:58:39 -19:08:56 SAAO R 480 2025-02-07 19:08:01 10:04:08 -22:58:43 SAAO R 480 2025-02-07 19:20:55 10:04:08 -22:58:43 SAAO R 480 2025-02-07 19:20:55 10:05:27 -21:03:50 SAAO R 480 2025-02-07 19:33:08 10:05:27 -21:03:50 SAAO R 480 2025-02-07 19:33:08 10:08:00 -17:14:03 SAAO R 480 2025-02-07 19:45:36 10:08:00 -17:14:03 SAAO R 480 2025-02-07 19:45:36 10:11:10 -24:53:37 SAAO R 480 2025-02-07 19:57:42 10:11:10 -24:53:37 SAAO R 480 2025-02-07 19:57:42 10:12:25 -22:58:43 SAAO R 480 2025-02-07 20:10:07 10:12:25 -22:58:43 SAAO R 480 2025-02-07 20:10:07 10:14:50 -19:08:56 SAAO R 480 2025-02-07 20:22:31 10:14:50 -19:08:56 SAAO R 480 2025-02-07 20:22:31 10:15:54 -28:43:24 SAAO R 480 2025-02-07 20:34:56 10:20:41 -22:58:43 SAAO R 480 2025-02-07 20:47:21 10:20:41 -22:58:43 SAAO R 480 2025-02-07 20:47:21 10:28:52 -30:00:00 SAAO R 480 2025-02-07 21:00:55 10:29:24 -34:00:00 SAAO R 600 2025-02-07 21:13:27 10:30:32 -26:48:31 SAAO R 600 2025-02-07 21:26:03 10:33:15 -28:43:24 SAAO R 480 2025-02-07 21:45:59 10:33:15 -28:43:24 SAAO R 480 2025-02-07 21:45:59 10:42:10 -36:00:00 SAAO R 480 2025-02-07 21:57:54 10:45:53 -42:00:00 SAAO R 480 2025-02-07 22:10:01 10:52:30 -46:00:00 SAAO R 480 2025-02-07 22:22:30 10:54:33 -44:00:00 SAAO R 480 2025-02-07 22:35:00 10:56:28 -42:00:00 SAAO R 480 2025-02-07 22:47:26 10:58:17 -40:00:00 SAAO R 480 2025-02-07 22:59:53 ------ We have reference images for part of the observed fields from the KMTNet Synoptic Survey of Southern Sky (KS4) project. The 7DT observations began on 2025-02-07 at 01:24 (UT), approximately 4 hours after the GW event. The pre-defined tiles were selected to overlap with the 90% credible region of the GW skymap. A wide-field search strategy was implemented, with each telescope pointing at a different area to maximize sky coverage. The observations were conducted using thirteen 7DT units, initially covering the region in the g-band, followed by r-band observations, with exposure times ranging from 3*100 sec to 6*100 sec per tile. As a result, we covered 590 tiles in the g-band and 316 tiles in the r-band, corresponding to approximately 590 deg^2 and 316 deg^2, respectively, within the targeted region. ------ TILENAME RA DEC EXPTIME[s] FILTER DATE-OBS[UTC] T17600 144.516 -4.245 300 g 2025-02-07T01:24:36 T17321 144.516 -5.094 300 g 2025-02-07T01:24:36 T23699 135.498 14.434 300 g 2025-02-07T01:24:41 T23428 136.324 13.585 300 g 2025-02-07T01:24:43 T23969 134.667 15.283 300 g 2025-02-07T01:24:44 T22608 137.455 11.038 300 g 2025-02-07T01:24:44 T21226 138.561 6.792 300 g 2025-02-07T01:24:45 T21504 139.061 7.642 300 g 2025-02-07T01:24:47 T22057 138.261 9.340 300 g 2025-02-07T01:24:47 T21781 139.061 8.491 300 g 2025-02-07T01:24:48 T20949 139.856 5.943 300 g 2025-02-07T01:24:50 T22058 139.565 9.340 300 g 2025-02-07T01:24:52 T19834 140.645 2.547 300 g 2025-02-07T01:24:52 T24774 133.483 17.830 300 g 2025-02-07T01:30:07 T24507 134.328 16.981 300 g 2025-02-07T01:30:09 T24239 135.167 16.132 300 g 2025-02-07T01:30:12 T23970 136.000 15.283 300 g 2025-02-07T01:30:14 T23700 136.827 14.434 300 g 2025-02-07T01:30:16 T22334 139.565 10.189 300 g 2025-02-07T01:30:16 T20392 140.645 4.245 300 g 2025-02-07T01:30:20 T20113 140.645 3.396 300 g 2025-02-07T01:30:20 T20671 140.645 5.094 300 g 2025-02-07T01:30:21 T19275 141.429 0.849 300 g 2025-02-07T01:30:24 T19555 141.429 1.698 300 g 2025-02-07T01:30:24 T20950 141.151 5.943 300 g 2025-02-07T01:30:27 T21228 141.151 6.792 300 g 2025-02-07T01:30:31 T21227 139.856 6.792 300 g 2025-02-07T01:35:41 T17879 144.516 -3.396 300 g 2025-02-07T01:35:44 T24775 134.831 17.830 300 g 2025-02-07T01:35:46 T17601 145.806 -4.245 300 g 2025-02-07T01:35:48 T24508 135.672 16.981 300 g 2025-02-07T01:35:50 T15384 146.618 -11.038 300 g 2025-02-07T01:35:51 T24240 136.506 16.132 300 g 2025-02-07T01:35:51 T19835 141.935 2.547 300 g 2025-02-07T01:35:54 T20393 141.935 4.245 300 g 2025-02-07T01:35:57 T20114 141.935 3.396 300 g 2025-02-07T01:35:58 T20672 141.935 5.094 300 g 2025-02-07T01:35:58 T18716 142.714 -0.849 300 g 2025-02-07T01:36:05 T18436 142.714 -1.698 300 g 2025-02-07T01:36:05 T19276 142.714 0.849 300 g 2025-02-07T01:41:13 T18996 142.714 0.000 300 g 2025-02-07T01:41:14 T17878 143.226 -3.396 300 g 2025-02-07T01:41:15 T19556 142.714 1.698 300 g 2025-02-07T01:41:16 T18157 143.226 -2.547 300 g 2025-02-07T01:41:22 T19836 143.226 2.547 300 g 2025-02-07T01:41:22 T20115 143.226 3.396 300 g 2025-02-07T01:41:22 T20394 143.226 4.245 300 g 2025-02-07T01:41:24 T18437 144.000 -1.698 300 g 2025-02-07T01:41:29 T18997 144.000 0.000 300 g 2025-02-07T01:41:31 T19277 144.000 0.849 300 g 2025-02-07T01:41:39 T19557 144.000 1.698 300 g 2025-02-07T01:41:40 T18158 144.516 -2.547 300 g 2025-02-07T01:41:44 T17043 145.036 -5.943 300 g 2025-02-07T01:46:45 T15934 144.783 -9.340 300 g 2025-02-07T01:46:46 T16765 145.036 -6.792 300 g 2025-02-07T01:46:49 T17322 145.806 -5.094 300 g 2025-02-07T01:46:51 T18159 145.806 -2.547 300 g 2025-02-07T01:46:55 T16766 146.331 -6.792 300 g 2025-02-07T01:46:57 T17044 146.331 -5.943 300 g 2025-02-07T01:46:57 T17880 145.806 -3.396 300 g 2025-02-07T01:46:58 T14836 146.374 -12.736 300 g 2025-02-07T01:47:01 T16212 146.859 -8.491 300 g 2025-02-07T01:47:03 T16489 146.859 -7.642 300 g 2025-02-07T01:47:14 T14564 146.912 -13.585 300 g 2025-02-07T01:47:21 T15110 147.153 -11.887 300 g 2025-02-07T01:47:23 T26863 129.882 24.623 300 g 2025-02-07T01:52:16 T17602 147.097 -4.245 300 g 2025-02-07T01:52:20 T15660 147.391 -10.189 300 g 2025-02-07T01:52:23 T15936 147.391 -9.340 300 g 2025-02-07T01:52:24 T14293 147.454 -14.434 300 g 2025-02-07T01:52:27 T15385 147.927 -11.038 300 g 2025-02-07T01:52:28 T14837 147.692 -12.736 300 g 2025-02-07T01:52:29 T14565 148.235 -13.585 300 g 2025-02-07T01:52:32 T15111 148.467 -11.887 300 g 2025-02-07T01:52:34 T14023 148.000 -15.283 300 g 2025-02-07T01:52:36 T15661 148.696 -10.189 300 g 2025-02-07T01:52:49 T13754 148.550 -16.132 300 g 2025-02-07T01:53:02 T14294 148.782 -14.434 300 g 2025-02-07T01:53:03 T27369 128.571 26.321 300 g 2025-02-07T01:57:45 T14838 149.011 -12.736 300 g 2025-02-07T01:57:55 T13486 149.104 -16.981 300 g 2025-02-07T01:57:57 T14566 149.559 -13.585 300 g 2025-02-07T01:57:58 T14024 149.333 -15.283 300 g 2025-02-07T01:57:59 T13755 149.888 -16.132 300 g 2025-02-07T01:57:59 T13219 149.663 -17.830 500 g 2025-02-07T01:58:00 T14295 150.111 -14.434 200 g 2025-02-07T01:58:04 T12688 150.000 -19.528 500 g 2025-02-07T01:58:06 T12953 150.226 -18.679 500 g 2025-02-07T01:58:12 T13487 150.448 -16.981 200 g 2025-02-07T02:00:01 T14025 150.667 -15.283 200 g 2025-02-07T02:00:24 T13220 151.011 -17.830 500 g 2025-02-07T02:00:36 T13757 152.565 -16.132 300 g 2025-02-07T03:18:11 T12689 151.364 -19.528 600 g 2025-02-07T03:18:13 T14296 151.439 -14.434 300 g 2025-02-07T03:18:15 T27870 129.194 28.019 300 g 2025-02-07T03:18:17 T13488 151.791 -16.981 300 g 2025-02-07T03:18:18 T13489 153.134 -16.981 300 g 2025-02-07T03:18:20 T12954 151.579 -18.679 600 g 2025-02-07T03:18:20 T11903 150.923 -22.075 600 g 2025-02-07T03:18:24 T14026 152.000 -15.283 300 g 2025-02-07T03:18:24 T12426 151.939 -20.377 600 g 2025-02-07T03:18:25 T13221 152.360 -17.830 600 g 2025-02-07T03:18:26 T12690 152.727 -19.528 600 g 2025-02-07T03:23:45 T11904 152.308 -22.075 600 g 2025-02-07T03:23:47 T11388 152.685 -23.774 600 g 2025-02-07T03:23:48 T12427 153.308 -20.377 600 g 2025-02-07T03:23:50 T11646 153.488 -22.925 600 g 2025-02-07T03:23:52 T11905 153.692 -22.075 600 g 2025-02-07T03:23:54 T12428 154.677 -20.377 600 g 2025-02-07T03:23:54 T12166 154.483 -21.226 600 g 2025-02-07T03:23:57 T04860 165.561 -48.396 300 g 2025-02-07T03:23:58 T11389 154.086 -23.774 600 g 2025-02-07T03:23:59 T11133 153.882 -24.623 600 g 2025-02-07T03:24:02 T10879 153.676 -25.472 600 g 2025-02-07T03:24:05 T05240 166.010 -46.698 600 g 2025-02-07T03:29:19 T06660 160.563 -40.755 600 g 2025-02-07T03:29:21 T05434 165.306 -45.849 600 g 2025-02-07T03:29:24 T04861 167.487 -48.396 600 g 2025-02-07T03:29:25 T05631 164.623 -45.000 600 g 2025-02-07T03:29:26 T05049 166.737 -47.547 600 g 2025-02-07T03:29:26 T10627 154.286 -26.321 600 g 2025-02-07T03:29:28 T10376 154.080 -27.170 600 g 2025-02-07T03:29:30 T06240 162.692 -42.453 600 g 2025-02-07T03:29:33 T11134 155.294 -24.623 600 g 2025-02-07T03:29:34 T10880 155.099 -25.472 600 g 2025-02-07T03:29:37 T07984 157.895 -35.660 600 g 2025-02-07T03:29:46 T06661 162.254 -40.755 600 g 2025-02-07T03:34:48 T10628 155.714 -26.321 600 g 2025-02-07T03:34:54 T05632 166.432 -45.000 600 g 2025-02-07T03:34:54 T06875 161.667 -39.906 600 g 2025-02-07T03:34:56 T05832 165.743 -44.151 600 g 2025-02-07T03:34:56 T05435 167.143 -45.849 600 g 2025-02-07T03:35:01 T06035 165.073 -43.302 600 g 2025-02-07T03:35:04 T10377 155.520 -27.170 600 g 2025-02-07T03:35:04 T05241 167.876 -46.698 600 g 2025-02-07T03:35:07 T06241 164.423 -42.453 600 g 2025-02-07T03:35:08 T05050 168.632 -47.547 600 g 2025-02-07T03:35:18 T06450 163.791 -41.604 600 g 2025-02-07T03:35:28 T04862 169.412 -48.396 600 g 2025-02-07T03:40:18 T10128 155.323 -28.019 600 g 2025-02-07T03:40:23 T07312 161.267 -38.208 600 g 2025-02-07T03:40:27 T08445 157.597 -33.962 600 g 2025-02-07T03:40:28 T09881 155.122 -28.868 600 g 2025-02-07T03:40:31 T04677 170.217 -49.245 600 g 2025-02-07T03:40:32 T09636 154.918 -29.717 600 g 2025-02-07T03:40:34 T08214 158.961 -34.811 600 g 2025-02-07T03:40:38 T06876 163.333 -39.906 600 g 2025-02-07T03:40:38 T06662 163.944 -40.755 600 g 2025-02-07T03:40:39 T07093 162.740 -39.057 600 g 2025-02-07T03:40:55 T10629 157.143 -26.321 600 g 2025-02-07T03:41:07 T12955 152.932 -18.679 600 g 2025-02-07T03:50:13 T10378 156.960 -27.170 600 g 2025-02-07T03:50:14 T10129 156.774 -28.019 600 g 2025-02-07T03:50:16 T07759 160.885 -36.509 600 g 2025-02-07T03:50:17 T08679 157.787 -33.113 600 g 2025-02-07T03:50:19 T06242 166.154 -42.453 600 g 2025-02-07T03:50:21 T06036 166.829 -43.302 600 g 2025-02-07T03:50:22 T05833 167.525 -44.151 600 g 2025-02-07T03:50:25 T05633 168.241 -45.000 600 g 2025-02-07T03:50:25 T09882 156.585 -28.868 600 g 2025-02-07T03:50:27 T05436 168.980 -45.849 600 g 2025-02-07T03:50:28 T05242 169.741 -46.698 600 g 2025-02-07T03:50:32 T06451 165.498 -41.604 600 g 2025-02-07T03:52:04 T08446 159.142 -33.962 600 g 2025-02-07T03:55:43 T07313 162.896 -38.208 600 g 2025-02-07T03:55:45 T05051 170.526 -47.547 600 g 2025-02-07T03:55:56 T03968 174.737 -52.642 600 g 2025-02-07T03:55:56 T09637 156.393 -29.717 600 g 2025-02-07T03:55:57 T07535 162.321 -37.358 600 g 2025-02-07T03:55:57 T04863 171.337 -48.396 600 g 2025-02-07T03:55:59 T08215 160.519 -34.811 600 g 2025-02-07T03:55:59 T07986 161.053 -35.660 600 g 2025-02-07T03:56:00 T04496 173.039 -50.094 600 g 2025-02-07T03:56:02 T04678 172.174 -49.245 600 g 2025-02-07T03:56:03 T04317 173.933 -50.943 600 g 2025-02-07T03:56:06 T10379 158.400 -27.170 600 g 2025-02-07T03:57:34 T08680 159.319 -33.113 600 g 2025-02-07T04:01:11 T04141 174.857 -51.792 600 g 2025-02-07T04:01:14 T07760 162.478 -36.509 600 g 2025-02-07T04:01:26 T08916 158.824 -32.264 600 g 2025-02-07T04:01:27 T08447 160.687 -33.962 600 g 2025-02-07T04:01:32 T09883 158.049 -28.868 600 g 2025-02-07T04:01:32 T06037 168.585 -43.302 600 g 2025-02-07T04:01:32 T05834 169.307 -44.151 600 g 2025-02-07T04:01:34 T09638 157.869 -29.717 600 g 2025-02-07T04:01:36 T05052 172.421 -47.547 600 g 2025-02-07T04:01:37 T09396 159.174 -30.566 600 g 2025-02-07T04:01:39 T27368 127.143 26.321 300 g 2025-02-07T04:01:42 T28361 126.885 29.717 300 g 2025-02-07T04:03:06 T26862 128.471 24.623 300 g 2025-02-07T04:06:44 T27620 128.160 27.170 300 g 2025-02-07T04:06:48 T27116 128.063 25.472 300 g 2025-02-07T04:06:59 T27869 127.742 28.019 300 g 2025-02-07T04:07:00 T28116 127.317 28.868 300 g 2025-02-07T04:07:04 T28362 128.361 29.717 300 g 2025-02-07T04:07:06 T26089 128.769 22.075 300 g 2025-02-07T04:07:07 T26606 128.872 23.774 300 g 2025-02-07T04:07:10 T28117 128.780 28.868 300 g 2025-02-07T04:07:13 T27117 129.486 25.472 300 g 2025-02-07T04:07:13 T27619 126.720 27.170 300 g 2025-02-07T04:07:13 T26349 129.767 22.925 300 g 2025-02-07T04:07:20 T27621 129.600 27.170 300 g 2025-02-07T04:08:37 T26090 130.154 22.075 300 g 2025-02-07T04:12:13 T26607 130.272 23.774 300 g 2025-02-07T04:12:17 T25567 130.038 20.377 300 g 2025-02-07T04:12:34 T27370 130.000 26.321 300 g 2025-02-07T04:12:35 T27871 130.645 28.019 300 g 2025-02-07T04:12:37 T25304 130.909 19.528 300 g 2025-02-07T04:12:38 T24772 130.787 17.830 300 g 2025-02-07T04:12:41 T25830 131.034 21.226 300 g 2025-02-07T04:12:42 T27622 131.040 27.170 300 g 2025-02-07T04:12:50 T27118 130.909 25.472 300 g 2025-02-07T04:12:50 T25039 131.278 18.679 300 g 2025-02-07T04:12:53 T25568 131.407 20.377 300 g 2025-02-07T04:13:00 T26350 131.163 22.925 300 g 2025-02-07T04:14:10 T27371 131.429 26.321 300 g 2025-02-07T04:17:43 T26864 131.294 24.623 300 g 2025-02-07T04:17:46 T26608 131.673 23.774 300 g 2025-02-07T04:18:08 T26091 131.538 22.075 300 g 2025-02-07T04:18:09 T24505 131.642 16.981 300 g 2025-02-07T04:18:10 T24773 132.135 17.830 300 g 2025-02-07T04:18:13 T25305 132.273 19.528 300 g 2025-02-07T04:18:13 T27119 132.332 25.472 300 g 2025-02-07T04:18:18 T26865 132.706 24.623 300 g 2025-02-07T04:19:41 T24237 132.491 16.132 300 g 2025-02-07T04:19:59 T25040 132.632 18.679 300 g 2025-02-07T04:20:04 T25831 132.414 21.226 300 g 2025-02-07T04:20:17 T26351 132.558 22.925 300 g 2025-02-07T04:20:30 T24506 132.985 16.981 300 g 2025-02-07T04:24:51 T26609 133.074 23.774 300 g 2025-02-07T04:24:54 T26092 132.923 22.075 300 g 2025-02-07T04:25:12 T23968 133.333 15.283 300 g 2025-02-07T04:25:17 T23426 133.676 13.585 300 g 2025-02-07T04:25:24 T25569 132.776 20.377 300 g 2025-02-07T04:25:24 T24238 133.829 16.132 300 g 2025-02-07T04:25:25 T25306 133.636 19.528 300 g 2025-02-07T04:25:27 T25832 133.793 21.226 300 g 2025-02-07T04:25:30 T26352 133.953 22.925 300 g 2025-02-07T04:25:34 T23698 134.170 14.434 300 g 2025-02-07T04:25:38 T25041 133.985 18.679 300 g 2025-02-07T04:25:57 T25570 134.144 20.377 300 g 2025-02-07T04:26:13 T26093 134.308 22.075 300 g 2025-02-07T04:30:21 T23154 134.505 12.736 300 g 2025-02-07T04:30:25 T23427 135.000 13.585 300 g 2025-02-07T04:30:43 T22606 134.836 11.038 300 g 2025-02-07T04:30:48 T25833 135.172 21.226 300 g 2025-02-07T04:30:56 T25307 135.000 19.528 300 g 2025-02-07T04:30:58 T22881 135.328 11.887 300 g 2025-02-07T04:31:00 T25042 135.338 18.679 300 g 2025-02-07T04:31:04 T25571 135.513 20.377 300 g 2025-02-07T04:31:05 T26094 135.692 22.075 300 g 2025-02-07T04:31:08 T22331 135.652 10.189 300 g 2025-02-07T04:31:14 T23155 135.824 12.736 300 g 2025-02-07T04:31:37 T22607 136.145 11.038 300 g 2025-02-07T04:31:54 T24776 136.180 17.830 300 g 2025-02-07T04:35:51 T25308 136.364 19.528 300 g 2025-02-07T04:35:55 T21779 136.462 8.491 300 g 2025-02-07T04:36:15 T22882 136.642 11.887 300 g 2025-02-07T04:36:18 T21502 136.462 7.642 300 g 2025-02-07T04:36:28 T25043 136.692 18.679 300 g 2025-02-07T04:36:33 T22332 136.957 10.189 300 g 2025-02-07T04:36:34 T22056 136.957 9.340 300 g 2025-02-07T04:36:40 T24509 137.015 16.981 300 g 2025-02-07T04:36:42 T23156 137.143 12.736 300 g 2025-02-07T04:36:43 T21225 137.266 6.792 300 g 2025-02-07T04:36:50 T20947 137.266 5.943 300 g 2025-02-07T04:37:19 T23971 137.333 15.283 300 g 2025-02-07T04:37:34 T21780 137.762 8.491 300 g 2025-02-07T04:41:20 T21503 137.762 7.642 300 g 2025-02-07T04:41:26 T23429 137.647 13.585 300 g 2025-02-07T04:41:46 T24241 137.844 16.132 300 g 2025-02-07T04:41:48 T20669 138.065 5.094 300 g 2025-02-07T04:41:59 T22333 138.261 10.189 300 g 2025-02-07T04:42:07 T22883 137.956 11.887 300 g 2025-02-07T04:42:07 T20390 138.065 4.245 300 g 2025-02-07T04:42:13 T24510 138.358 16.981 300 g 2025-02-07T04:42:17 T23701 138.155 14.434 300 g 2025-02-07T04:42:17 T23157 138.462 12.736 300 g 2025-02-07T04:42:26 T20948 138.561 5.943 300 g 2025-02-07T04:42:59 T23972 138.667 15.283 300 g 2025-02-07T04:43:14 T22609 138.764 11.038 300 g 2025-02-07T04:46:50 T23430 138.971 13.585 300 g 2025-02-07T04:46:56 T20670 139.355 5.094 300 g 2025-02-07T04:47:18 T22884 139.270 11.887 300 g 2025-02-07T04:47:19 T20391 139.355 4.245 300 g 2025-02-07T04:47:31 T20112 139.355 3.396 300 g 2025-02-07T04:47:39 T19833 139.355 2.547 300 g 2025-02-07T04:47:41 T23158 139.780 12.736 300 g 2025-02-07T04:47:48 T19554 140.143 1.698 300 g 2025-02-07T04:47:53 T22610 140.073 11.038 300 g 2025-02-07T04:47:53 T19274 140.143 0.849 300 g 2025-02-07T04:48:01 T21505 140.361 7.642 300 g 2025-02-07T04:48:40 T18994 140.143 0.000 300 g 2025-02-07T04:48:56 T21782 140.361 8.491 300 g 2025-02-07T04:52:19 T22335 140.870 10.189 300 g 2025-02-07T04:52:25 T18995 141.429 0.000 300 g 2025-02-07T04:52:50 T18715 141.429 -0.849 300 g 2025-02-07T04:53:03 T21783 141.661 8.491 300 g 2025-02-07T04:53:14 T18435 141.429 -1.698 300 g 2025-02-07T04:53:14 T21506 141.661 7.642 300 g 2025-02-07T04:53:23 T17877 141.935 -3.396 300 g 2025-02-07T04:53:30 T17598 141.935 -4.245 300 g 2025-02-07T04:53:30 T17319 141.935 -5.094 300 g 2025-02-07T04:53:37 T18156 141.935 -2.547 300 g 2025-02-07T04:54:20 T22059 140.870 9.340 300 g 2025-02-07T04:54:24 T21229 142.446 6.792 300 g 2025-02-07T04:54:37 T17041 142.446 -5.943 300 g 2025-02-07T04:57:49 T20951 142.446 5.943 300 g 2025-02-07T04:57:54 T16763 142.446 -6.792 300 g 2025-02-07T04:58:20 T21507 142.960 7.642 300 g 2025-02-07T04:58:34 T16486 142.960 -7.642 300 g 2025-02-07T04:58:47 T16209 142.960 -8.491 300 g 2025-02-07T04:58:49 T20673 143.226 5.094 300 g 2025-02-07T04:58:58 T17320 143.226 -5.094 300 g 2025-02-07T04:59:03 T17599 143.226 -4.245 300 g 2025-02-07T04:59:07 T15933 143.478 -9.340 300 g 2025-02-07T04:59:13 T15657 143.478 -10.189 300 g 2025-02-07T04:59:55 T20952 143.741 5.943 300 g 2025-02-07T05:00:01 T17042 143.741 -5.943 300 g 2025-02-07T05:00:17 T16764 143.741 -6.792 300 g 2025-02-07T05:03:18 T18717 144.000 -0.849 300 g 2025-02-07T05:03:24 T16487 144.260 -7.642 300 g 2025-02-07T05:03:50 T16210 144.260 -8.491 300 g 2025-02-07T05:04:06 T20395 144.516 4.245 300 g 2025-02-07T05:04:20 T20116 144.516 3.396 300 g 2025-02-07T05:04:22 T19837 144.516 2.547 300 g 2025-02-07T05:04:32 T15108 144.526 -11.887 300 g 2025-02-07T05:04:36 T15658 144.783 -10.189 300 g 2025-02-07T05:04:45 T19278 145.286 0.849 300 g 2025-02-07T05:04:49 T18998 145.286 0.000 300 g 2025-02-07T05:05:27 T18718 145.286 -0.849 300 g 2025-02-07T05:05:41 T18438 145.286 -1.698 300 g 2025-02-07T05:05:58 T14835 145.055 -12.736 300 g 2025-02-07T05:08:48 T19558 145.286 1.698 300 g 2025-02-07T05:08:54 T15383 145.309 -11.038 300 g 2025-02-07T05:09:20 T16211 145.560 -8.491 300 g 2025-02-07T05:09:38 T16488 145.560 -7.642 300 g 2025-02-07T05:09:53 T14563 145.588 -13.585 300 g 2025-02-07T05:09:56 T15109 145.839 -11.887 300 g 2025-02-07T05:10:07 T15935 146.087 -9.340 300 g 2025-02-07T05:10:10 T15659 146.087 -10.189 300 g 2025-02-07T05:10:20 T18719 146.571 -0.849 300 g 2025-02-07T05:10:24 T14292 146.125 -14.434 300 g 2025-02-07T05:10:58 T18439 146.571 -1.698 300 g 2025-02-07T05:11:20 T18999 146.571 0.000 300 g 2025-02-07T05:11:38 T14022 146.667 -15.283 300 g 2025-02-07T05:14:17 T18160 147.097 -2.547 300 g 2025-02-07T05:14:24 T17881 147.097 -3.396 300 g 2025-02-07T05:14:52 T17323 147.097 -5.094 300 g 2025-02-07T05:15:10 T13753 147.212 -16.132 300 g 2025-02-07T05:15:26 T17045 147.626 -5.943 300 g 2025-02-07T05:15:30 T16767 147.626 -6.792 300 g 2025-02-07T05:15:41 T16490 148.159 -7.642 300 g 2025-02-07T05:15:44 T16213 148.159 -8.491 300 g 2025-02-07T05:15:56 T13485 147.761 -16.981 300 g 2025-02-07T05:15:58 T17603 148.387 -4.245 300 g 2025-02-07T05:16:30 T17324 148.387 -5.094 300 g 2025-02-07T05:17:00 T15937 148.696 -9.340 300 g 2025-02-07T05:17:20 T13218 148.315 -17.830 300 g 2025-02-07T05:19:47 T17046 148.921 -5.943 300 g 2025-02-07T05:19:54 T16768 148.921 -6.792 300 g 2025-02-07T05:20:22 T12687 148.636 -19.528 300 g 2025-02-07T05:20:42 T15386 149.236 -11.038 300 g 2025-02-07T05:20:57 T12952 148.872 -18.679 300 g 2025-02-07T05:21:05 T16491 149.458 -7.642 300 g 2025-02-07T05:21:16 T16214 149.458 -8.491 300 g 2025-02-07T05:22:52 T01256 237.600 -69.623 600 g 2025-02-07T05:38:49 T01258 244.800 -69.623 600 g 2025-02-07T05:38:51 T01463 235.514 -67.925 600 g 2025-02-07T05:38:52 T01160 247.500 -70.472 600 g 2025-02-07T05:38:52 T01358 237.670 -68.774 600 g 2025-02-07T05:38:54 T01465 242.243 -67.925 600 g 2025-02-07T05:38:59 T01360 244.660 -68.774 600 g 2025-02-07T05:38:59 T01161 251.250 -70.472 600 g 2025-02-07T05:39:00 T01159 243.750 -70.472 600 g 2025-02-07T05:39:00 T01259 248.400 -69.623 600 g 2025-02-07T05:39:00 T01361 248.155 -68.774 600 g 2025-02-07T05:39:01 T01257 241.200 -69.623 600 g 2025-02-07T05:40:37 T01467 248.972 -67.925 600 g 2025-02-07T05:40:40 T01576 246.486 -67.075 600 g 2025-02-07T05:44:21 T01260 252.000 -69.623 600 g 2025-02-07T05:44:25 T04316 171.910 -50.943 600 g 2025-02-07T05:44:27 T04494 169.061 -50.094 600 g 2025-02-07T05:44:27 T04495 171.050 -50.094 600 g 2025-02-07T05:44:32 T03967 172.632 -52.642 300 g 2025-02-07T05:44:34 T05243 171.606 -46.698 600 g 2025-02-07T05:44:37 T04864 173.262 -48.396 600 g 2025-02-07T05:44:38 T04679 174.130 -49.245 600 g 2025-02-07T05:44:39 T04497 175.028 -50.094 600 g 2025-02-07T05:44:40 T04318 175.955 -50.943 600 g 2025-02-07T05:44:41 T01063 238.696 -71.321 600 g 2025-02-07T05:46:11 T01362 251.650 -68.774 600 g 2025-02-07T05:46:19 T01255 234.000 -69.623 600 g 2025-02-07T05:49:51 T01357 234.175 -68.774 600 g 2025-02-07T05:49:55 T01462 232.150 -67.925 600 g 2025-02-07T05:50:00 T01064 242.609 -71.321 600 g 2025-02-07T05:50:05 T01158 240.000 -70.472 600 g 2025-02-07T05:50:10 T01572 233.514 -67.075 600 g 2025-02-07T05:50:14 T01065 246.522 -71.321 600 g 2025-02-07T05:50:17 T01066 250.435 -71.321 600 g 2025-02-07T05:50:18 T01359 241.165 -68.774 600 g 2025-02-07T05:50:20 T01466 245.607 -67.925 600 g 2025-02-07T05:50:27 T01067 254.348 -71.321 600 g 2025-02-07T05:50:29 T01468 252.336 -67.925 600 g 2025-02-07T05:51:48 T01162 255.000 -70.472 600 g 2025-02-07T05:52:00 T01575 243.243 -67.075 600 g 2025-02-07T05:55:20 T01689 244.174 -66.226 600 g 2025-02-07T05:55:30 T01577 249.730 -67.075 600 g 2025-02-07T05:55:32 T01690 247.304 -66.226 600 g 2025-02-07T05:55:37 T01691 250.435 -66.226 600 g 2025-02-07T05:55:42 T11390 155.486 -23.774 600 g 2025-02-07T05:55:51 T11906 155.077 -22.075 600 g 2025-02-07T05:55:52 T08914 155.798 -32.264 600 g 2025-02-07T05:55:54 T08444 156.052 -33.962 600 g 2025-02-07T05:56:10 T11648 156.279 -22.925 600 g 2025-02-07T05:56:11 T01578 252.973 -67.075 600 g 2025-02-07T05:57:22 T11647 154.884 -22.925 600 g 2025-02-07T05:57:29 T01261 255.600 -69.623 600 g 2025-02-07T05:57:37 T01363 255.146 -68.774 600 g 2025-02-07T06:00:50 T10881 156.522 -25.472 600 g 2025-02-07T06:01:06 T11135 156.706 -24.623 600 g 2025-02-07T06:01:07 T11391 156.887 -23.774 600 g 2025-02-07T06:01:11 T08678 156.255 -33.113 600 g 2025-02-07T06:01:17 T08213 157.403 -34.811 600 g 2025-02-07T06:01:24 T08915 157.311 -32.264 600 g 2025-02-07T06:01:30 T07757 157.699 -36.509 600 g 2025-02-07T06:01:31 T09154 157.500 -31.415 600 g 2025-02-07T06:01:49 T07533 159.107 -37.358 600 g 2025-02-07T06:01:54 T10130 158.226 -28.019 600 g 2025-02-07T06:02:56 T09395 157.686 -30.566 600 g 2025-02-07T06:03:02 T10630 158.571 -26.321 600 g 2025-02-07T06:03:15 T01469 255.701 -67.925 600 g 2025-02-07T06:06:17 T07091 159.452 -39.057 600 g 2025-02-07T06:06:42 T01163 258.750 -70.472 600 g 2025-02-07T06:06:43 T07758 159.292 -36.509 600 g 2025-02-07T06:06:44 T07311 159.638 -38.208 600 g 2025-02-07T06:06:49 T07985 159.474 -35.660 600 g 2025-02-07T06:06:56 T06874 160.000 -39.906 600 g 2025-02-07T06:07:07 T06448 160.379 -41.604 600 g 2025-02-07T06:07:09 T09155 159.000 -31.415 600 g 2025-02-07T06:07:31 T06239 160.962 -42.453 600 g 2025-02-07T06:07:35 T10131 159.677 -28.019 600 g 2025-02-07T06:08:31 T09884 159.512 -28.868 600 g 2025-02-07T06:08:33 T09639 159.344 -29.717 600 g 2025-02-07T06:08:51 T07534 160.714 -37.358 600 g 2025-02-07T06:11:52 T01262 259.200 -69.623 600 g 2025-02-07T06:12:12 T08917 160.336 -32.264 600 g 2025-02-07T06:12:17 T07092 161.096 -39.057 600 g 2025-02-07T06:12:18 T06033 161.561 -43.302 600 g 2025-02-07T06:12:20 T05830 162.178 -44.151 600 g 2025-02-07T06:12:29 T08681 160.851 -33.113 600 g 2025-02-07T06:12:42 T06449 162.085 -41.604 600 g 2025-02-07T06:12:43 T09156 160.500 -31.415 600 g 2025-02-07T06:13:11 T01364 258.641 -68.774 600 g 2025-02-07T06:13:20 T05433 163.469 -45.849 600 g 2025-02-07T06:14:06 T05630 162.814 -45.000 600 g 2025-02-07T06:14:08 T09397 160.661 -30.566 600 g 2025-02-07T06:14:27 T08216 162.078 -34.811 600 g 2025-02-07T06:17:21 T06034 163.317 -43.302 600 g 2025-02-07T06:17:47 T07987 162.632 -35.660 600 g 2025-02-07T06:17:49 T08448 162.232 -33.962 600 g 2025-02-07T06:17:51 T05239 164.145 -46.698 600 g 2025-02-07T06:17:55 T05831 163.960 -44.151 600 g 2025-02-07T06:18:01 T08682 162.383 -33.113 600 g 2025-02-07T06:18:18 T01470 259.065 -67.925 600 g 2025-02-07T06:18:25 T05048 164.842 -47.547 600 g 2025-02-07T06:18:52 T07536 163.929 -37.358 600 g 2025-02-07T06:19:04 T07094 164.384 -39.057 600 g 2025-02-07T06:19:37 T07761 164.071 -36.509 600 g 2025-02-07T06:19:44 T07314 164.525 -38.208 600 g 2025-02-07T06:20:03 T06877 165.000 -39.906 600 g 2025-02-07T06:22:50 T04675 166.304 -49.245 600 g 2025-02-07T06:23:16 T06663 165.634 -40.755 600 g 2025-02-07T06:23:20 T04493 167.072 -50.094 600 g 2025-02-07T06:23:26 T07095 166.027 -39.057 600 g 2025-02-07T06:23:30 T04676 168.261 -49.245 600 g 2025-02-07T06:23:36 T06452 167.204 -41.604 600 g 2025-02-07T06:23:54 T03966 170.526 -52.642 600 g 2025-02-07T06:25:10 T04139 170.743 -51.792 600 g 2025-02-07T06:25:23 T06243 167.885 -42.453 600 g 2025-02-07T06:25:35 T03797 171.429 -53.491 600 g 2025-02-07T06:25:40 T05634 170.050 -45.000 600 g 2025-02-07T06:26:25 T04315 169.888 -50.943 600 g 2025-02-07T06:26:39 T03631 172.364 -54.340 600 g 2025-02-07T06:30:00 T04140 172.800 -51.792 600 g 2025-02-07T06:30:29 T05437 170.816 -45.849 600 g 2025-02-07T06:30:30 T03798 173.571 -53.491 600 g 2025-02-07T06:30:42 T03309 175.443 -56.038 600 g 2025-02-07T06:30:43 T03632 174.545 -54.340 600 g 2025-02-07T06:30:45 T03469 175.556 -55.189 600 g 2025-02-07T06:30:51 T03000 176.424 -57.736 600 g 2025-02-07T06:31:01 T03799 175.714 -53.491 600 g 2025-02-07T06:31:11 T03153 176.516 -56.887 600 g 2025-02-07T06:31:11 T02851 177.568 -58.585 600 g 2025-02-07T06:31:17 T03633 176.727 -54.340 600 g 2025-02-07T06:32:05 T03310 177.722 -56.038 600 g 2025-02-07T06:32:21 T03969 176.842 -52.642 600 g 2025-02-07T06:35:29 T04142 176.914 -51.792 600 g 2025-02-07T06:35:59 T03470 177.778 -55.189 600 g 2025-02-07T06:36:00 T03800 177.857 -53.491 600 g 2025-02-07T06:36:14 T03001 178.808 -57.736 600 g 2025-02-07T06:36:16 T03154 178.839 -56.887 600 g 2025-02-07T06:36:20 T04498 177.017 -50.094 600 g 2025-02-07T06:36:24 T02706 180.000 -59.434 600 g 2025-02-07T06:36:39 T03634 178.909 -54.340 600 g 2025-02-07T06:36:46 T02852 180.000 -58.585 600 g 2025-02-07T06:36:47 T04319 177.978 -50.943 600 g 2025-02-07T06:36:53 T02564 181.277 -60.283 600 g 2025-02-07T06:37:45 T03311 180.000 -56.038 600 g 2025-02-07T06:38:03 T03970 178.947 -52.642 600 g 2025-02-07T06:40:58 T03471 180.000 -55.189 600 g 2025-02-07T06:41:29 T03002 181.192 -57.736 600 g 2025-02-07T06:41:31 T03801 180.000 -53.491 600 g 2025-02-07T06:41:46 T03155 181.161 -56.887 600 g 2025-02-07T06:41:48 T02707 182.500 -59.434 600 g 2025-02-07T06:41:54 T02853 182.432 -58.585 600 g 2025-02-07T06:41:58 T02426 183.942 -61.132 600 g 2025-02-07T06:42:22 T02291 184.060 -61.981 600 g 2025-02-07T06:42:22 T02565 183.830 -60.283 600 g 2025-02-07T06:43:24 T03472 182.222 -55.189 600 g 2025-02-07T06:43:44 T03635 181.091 -54.340 600 g 2025-02-07T06:43:51 T03312 182.278 -56.038 600 g 2025-02-07T06:44:10 T03003 183.576 -57.736 600 g 2025-02-07T06:46:28 T02160 185.538 -62.830 600 g 2025-02-07T06:46:58 T03156 183.484 -56.887 600 g 2025-02-07T06:47:01 T02708 185.000 -59.434 600 g 2025-02-07T06:47:19 T02854 184.865 -58.585 600 g 2025-02-07T06:47:22 T03313 184.557 -56.038 600 g 2025-02-07T06:47:29 T02292 186.767 -61.981 600 g 2025-02-07T06:47:33 T02427 186.569 -61.132 600 g 2025-02-07T06:47:57 T02566 186.383 -60.283 600 g 2025-02-07T06:47:59 T03004 185.960 -57.736 600 g 2025-02-07T06:49:02 T01909 188.852 -64.528 600 g 2025-02-07T06:49:25 T03157 185.806 -56.887 600 g 2025-02-07T06:49:29 T02033 188.571 -63.679 600 g 2025-02-07T06:49:46 T02161 188.308 -62.830 600 g 2025-02-07T06:51:57 T02709 187.500 -59.434 600 g 2025-02-07T06:52:27 T01789 190.588 -65.377 600 g 2025-02-07T06:52:33 T02293 189.474 -61.981 600 g 2025-02-07T06:52:52 T02428 189.197 -61.132 600 g 2025-02-07T06:52:56 T02567 188.936 -60.283 600 g 2025-02-07T06:53:05 T01910 191.803 -64.528 600 g 2025-02-07T06:53:07 T02034 191.429 -63.679 600 g 2025-02-07T06:53:31 T02162 191.077 -62.830 600 g 2025-02-07T06:53:33 T01790 193.613 -65.377 600 g 2025-02-07T06:54:42 T12165 153.103 -21.226 600 g 2025-02-07T06:55:00 T12164 151.724 -21.226 600 g 2025-02-07T06:55:06 T11645 152.093 -22.925 600 g 2025-02-07T06:55:20 T09153 156.000 -31.415 600 g 2025-02-07T06:57:28 T12425 150.570 -20.377 600 g 2025-02-07T06:57:59 T11132 152.471 -24.623 600 g 2025-02-07T06:58:03 T10626 152.857 -26.321 600 g 2025-02-07T06:58:28 T10878 152.253 -25.472 600 g 2025-02-07T06:58:37 T11387 151.284 -23.774 600 g 2025-02-07T06:58:40 T10127 153.871 -28.019 600 g 2025-02-07T06:59:02 T10375 152.640 -27.170 600 g 2025-02-07T06:59:05 T09394 156.198 -30.566 600 g 2025-02-07T06:59:59 T09393 154.711 -30.566 600 g 2025-02-07T07:00:20 T09880 153.659 -28.868 600 g 2025-02-07T07:00:37 T01253 226.800 -69.623 600 g 2025-02-07T07:00:53 T01155 228.750 -70.472 600 g 2025-02-07T07:01:04 T01061 230.870 -71.321 600 g 2025-02-07T07:03:03 T01460 225.421 -67.925 600 g 2025-02-07T07:03:34 T01355 227.184 -68.774 600 g 2025-02-07T07:03:41 T01254 230.400 -69.623 600 g 2025-02-07T07:04:06 T01156 232.500 -70.472 600 g 2025-02-07T07:04:17 T01062 234.783 -71.321 600 g 2025-02-07T07:04:19 T01570 227.027 -67.075 600 g 2025-02-07T07:04:43 T01461 228.785 -67.925 600 g 2025-02-07T07:04:46 T01356 230.680 -68.774 600 g 2025-02-07T07:05:37 T01157 236.250 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2025-02-07T07:16:55 T04317 173.933 -50.943 600 r 2025-02-07T07:17:09 T05436 168.980 -45.849 600 r 2025-02-07T07:17:14 T05050 168.632 -47.547 600 r 2025-02-07T07:17:39 T05241 167.876 -46.698 600 r 2025-02-07T07:17:49 T05435 167.143 -45.849 600 r 2025-02-07T07:18:32 T05240 166.010 -46.698 600 r 2025-02-07T07:19:14 T01256 237.600 -69.623 600 r 2025-02-07T07:19:22 T01358 237.670 -68.774 600 r 2025-02-07T07:19:45 T01463 235.514 -67.925 600 r 2025-02-07T07:19:59 T01257 241.200 -69.623 600 r 2025-02-07T07:21:18 T01159 243.750 -70.472 600 r 2025-02-07T07:21:53 T01258 244.800 -69.623 600 r 2025-02-07T07:22:03 T01160 247.500 -70.472 600 r 2025-02-07T07:22:32 T01465 242.243 -67.925 600 r 2025-02-07T07:22:49 T01360 244.660 -68.774 600 r 2025-02-07T07:22:52 T01259 248.400 -69.623 600 r 2025-02-07T07:23:20 T01161 251.250 -70.472 600 r 2025-02-07T07:23:33 T01361 248.155 -68.774 600 r 2025-02-07T07:24:10 T01260 252.000 -69.623 600 r 2025-02-07T07:24:55 T01576 246.486 -67.075 600 r 2025-02-07T07:25:02 T01467 248.972 -67.925 600 r 2025-02-07T07:25:25 T01362 251.650 -68.774 600 r 2025-02-07T07:25:41 T01468 252.336 -67.925 600 r 2025-02-07T07:26:48 T01363 255.146 -68.774 600 r 2025-02-07T07:27:23 T01469 255.701 -67.925 600 r 2025-02-07T07:27:38 T01364 258.641 -68.774 600 r 2025-02-07T07:28:05 T04318 175.955 -50.943 600 r 2025-02-07T07:28:22 T04497 175.028 -50.094 600 r 2025-02-07T07:28:27 T03968 174.737 -52.642 600 r 2025-02-07T07:28:54 T04679 174.130 -49.245 600 r 2025-02-07T07:29:06 T03967 172.632 -52.642 600 r 2025-02-07T07:29:44 T04496 173.039 -50.094 600 r 2025-02-07T07:30:29 T04864 173.262 -48.396 600 r 2025-02-07T07:30:42 T04316 171.910 -50.943 600 r 2025-02-07T07:31:00 T04678 172.174 -49.245 600 r 2025-02-07T07:31:24 T05052 172.421 -47.547 600 r 2025-02-07T07:32:23 T04495 171.050 -50.094 600 r 2025-02-07T07:32:57 T04863 171.337 -48.396 600 r 2025-02-07T07:33:11 T05243 171.606 -46.698 600 r 2025-02-07T07:33:39 T04677 170.217 -49.245 600 r 2025-02-07T07:33:50 T05051 170.526 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2025-02-07T07:42:39 T06661 162.254 -40.755 600 r 2025-02-07T07:43:22 T07093 162.740 -39.057 600 r 2025-02-07T07:43:57 T07313 162.896 -38.208 600 r 2025-02-07T07:44:11 T06660 160.563 -40.755 600 r 2025-02-07T07:44:35 T01255 234.000 -69.623 600 r 2025-02-07T07:44:58 T01063 238.696 -71.321 600 r 2025-02-07T07:45:07 T01462 232.150 -67.925 600 r 2025-02-07T07:45:33 T01357 234.175 -68.774 600 r 2025-02-07T07:45:46 T07535 162.321 -37.358 600 r 2025-02-07T07:46:11 T01158 240.000 -70.472 600 r 2025-02-07T07:47:09 T01572 233.514 -67.075 600 r 2025-02-07T07:47:44 T01064 242.609 -71.321 600 r 2025-02-07T07:47:46 T01065 246.522 -71.321 600 r 2025-02-07T07:48:26 T01359 241.165 -68.774 600 r 2025-02-07T07:48:56 T01066 250.435 -71.321 600 r 2025-02-07T07:49:32 T01067 254.348 -71.321 600 r 2025-02-07T07:49:50 T01575 243.243 -67.075 600 r 2025-02-07T07:50:13 T01466 245.607 -67.925 600 r 2025-02-07T07:50:35 T01162 255.000 -70.472 600 r 2025-02-07T07:50:43 T01689 244.174 -66.226 600 r 2025-02-07T07:51:10 T01261 255.600 -69.623 600 r 2025-02-07T07:51:29 T01163 258.750 -70.472 600 r 2025-02-07T07:51:50 T01690 247.304 -66.226 600 r 2025-02-07T07:52:46 T01577 249.730 -67.075 600 r 2025-02-07T07:53:25 T01262 259.200 -69.623 600 r 2025-02-07T07:53:33 T01691 250.435 -66.226 600 r 2025-02-07T07:54:09 T01578 252.973 -67.075 600 r 2025-02-07T07:54:26 T01470 259.065 -67.925 600 r 2025-02-07T07:55:03 T08215 160.519 -34.811 600 r 2025-02-07T07:55:25 T08214 158.961 -34.811 600 r 2025-02-07T07:55:46 T08446 159.142 -33.962 600 r 2025-02-07T07:56:09 T08445 157.597 -33.962 600 r 2025-02-07T07:56:20 T08679 157.787 -33.113 600 r 2025-02-07T07:56:42 T10378 156.960 -27.170 600 r 2025-02-07T07:57:05 T10129 156.774 -28.019 600 r 2025-02-07T07:57:25 T10628 155.714 -26.321 600 r 2025-02-07T07:58:20 T10880 155.099 -25.472 600 r 2025-02-07T07:59:01 T11389 154.086 -23.774 600 r 2025-02-07T07:59:16 T09882 156.585 -28.868 600 r 2025-02-07T07:59:52 T11646 153.488 -22.925 600 r 2025-02-07T08:00:02 T10128 155.323 -28.019 600 r 2025-02-07T08:00:38 T10627 154.286 -26.321 600 r 2025-02-07T08:00:55 T10879 153.676 -25.472 600 r 2025-02-07T08:01:16 T09881 155.122 -28.868 600 r 2025-02-07T08:01:39 T12953 150.226 -18.679 600 r 2025-02-07T08:01:52 T02427 186.569 -61.132 600 r 2025-02-07T08:02:19 T02292 186.767 -61.981 600 r 2025-02-07T08:02:43 T02709 187.500 -59.434 600 r 2025-02-07T08:03:00 T02161 188.308 -62.830 600 r 2025-02-07T08:04:00 T02033 188.571 -63.679 600 r 2025-02-07T08:04:39 T02567 188.936 -60.283 600 r 2025-02-07T08:05:02 T02428 189.197 -61.132 600 r 2025-02-07T08:05:33 T01909 188.852 -64.528 600 r 2025-02-07T08:05:36 T02293 189.474 -61.981 600 r 2025-02-07T08:06:10 T02566 186.383 -60.283 600 r 2025-02-07T08:06:28 T01789 190.588 -65.377 600 r 2025-02-07T08:06:54 T02160 185.538 -62.830 600 r 2025-02-07T08:07:16 T03004 185.960 -57.736 600 r 2025-02-07T08:07:27 T02162 191.077 -62.830 600 r 2025-02-07T08:07:54 T02034 191.429 -63.679 600 r 2025-02-07T08:08:19 T01910 191.803 -64.528 600 r 2025-02-07T08:08:32 T03157 185.806 -56.887 600 r 2025-02-07T08:09:30 T01790 193.613 -65.377 600 r 2025-02-07T08:10:16 T02708 185.000 -59.434 600 r 2025-02-07T08:10:37 T02854 184.865 -58.585 600 r 2025-02-07T08:11:03 T02291 184.060 -61.981 600 r 2025-02-07T08:11:14 T03313 184.557 -56.038 600 r 2025-02-07T08:11:38 T02426 183.942 -61.132 600 r 2025-02-07T08:11:56 T02565 183.830 -60.283 600 r 2025-02-07T08:12:23 T03003 183.576 -57.736 600 r 2025-02-07T08:12:46 T03156 183.484 -56.887 600 r 2025-02-07T08:12:58 T02707 182.500 -59.434 600 r 2025-02-07T08:13:24 T02853 182.432 -58.585 600 r 2025-02-07T08:13:49 T03312 182.278 -56.038 600 r 2025-02-07T08:14:02 T02564 181.277 -60.283 600 r 2025-02-07T08:14:58 T03472 182.222 -55.189 600 r 2025-02-07T08:15:47 T03002 181.192 -57.736 600 r 2025-02-07T08:16:13 T03155 181.161 -56.887 600 r 2025-02-07T08:16:31 T02706 180.000 -59.434 600 r 2025-02-07T08:16:52 T03635 181.091 -54.340 600 r 2025-02-07T08:17:08 T02852 180.000 -58.585 600 r 2025-02-07T08:17:24 T03311 180.000 -56.038 600 r 2025-02-07T08:19:30 T03471 180.000 -55.189 600 r 2025-02-07T08:19:52 T03801 180.000 -53.491 600 r 2025-02-07T08:20:06 T03001 178.808 -57.736 600 r 2025-02-07T08:20:28 T03154 178.839 -56.887 600 r 2025-02-07T08:20:56 T03634 178.909 -54.340 600 r 2025-02-07T08:21:10 T02851 177.568 -58.585 600 r 2025-02-07T08:22:02 T03970 178.947 -52.642 600 r 2025-02-07T08:22:53 T03310 177.722 -56.038 600 r 2025-02-07T08:23:37 T03000 176.424 -57.736 600 r 2025-02-07T08:23:39 T03470 177.778 -55.189 600 r 2025-02-07T08:24:14 T03153 176.516 -56.887 600 r 2025-02-07T08:24:29 T03800 177.857 -53.491 600 r 2025-02-07T08:24:29 T03633 176.727 -54.340 600 r 2025-02-07T08:24:59 T04319 177.978 -50.943 600 r 2025-02-07T08:25:21 T03969 176.842 -52.642 600 r 2025-02-07T08:25:38 T03309 175.443 -56.038 600 r 2025-02-07T08:25:57 T04142 176.914 -51.792 600 r 2025-02-07T08:26:26 T03469 175.556 -55.189 600 r 2025-02-07T08:26:39 T03799 175.714 -53.491 600 r 2025-02-07T08:27:32 T04498 177.017 -50.094 600 r 2025-02-07T08:28:23 T01253 226.800 -69.623 600 r 2025-02-07T08:29:10 T01155 228.750 -70.472 600 r 2025-02-07T08:29:23 T01460 225.421 -67.925 600 r 2025-02-07T08:29:47 T01355 227.184 -68.774 600 r 2025-02-07T08:30:04 T01061 230.870 -71.321 600 r 2025-02-07T08:30:14 T01254 230.400 -69.623 600 r 2025-02-07T08:30:36 T01570 227.027 -67.075 600 r 2025-02-07T08:31:01 T01461 228.785 -67.925 600 r 2025-02-07T08:31:16 T01156 232.500 -70.472 600 r 2025-02-07T08:31:35 T01356 230.680 -68.774 600 r 2025-02-07T08:32:07 T01062 234.783 -71.321 600 r 2025-02-07T08:32:15 T01571 230.270 -67.075 600 r 2025-02-07T08:33:11 T01157 236.250 -70.472 600 r 2025-02-07T08:34:05 T01685 231.652 -66.226 600 r 2025-02-07T08:34:39 T03632 174.545 -54.340 600 r 2025-02-07T08:35:04 T01686 234.783 -66.226 600 r 2025-02-07T08:35:18 T01573 236.757 -67.075 600 r 2025-02-07T08:35:37 T01464 238.879 -67.925 600 r 2025-02-07T08:35:58 T01687 237.913 -66.226 600 r 2025-02-07T08:36:09 T01574 240.000 -67.075 600 r 2025-02-07T08:36:38 T01688 241.043 -66.226 600 r 2025-02-07T08:36:52 T03798 173.571 -53.491 600 r 2025-02-07T08:37:09 T03631 172.364 -54.340 600 r 2025-02-07T08:37:48 T01068 258.261 -71.321 600 r 2025-02-07T08:37:49 T01069 262.174 -71.321 600 r 2025-02-07T08:38:50 T01164 262.500 -70.472 600 r 2025-02-07T08:39:46 T01692 253.565 -66.226 600 r 2025-02-07T08:40:10 T01579 256.216 -67.075 600 r 2025-02-07T08:40:50 T01263 262.800 -69.623 600 r 2025-02-07T08:40:53 T01365 262.136 -68.774 600 r 2025-02-07T08:41:11 T01693 256.696 -66.226 600 r 2025-02-07T08:41:42 T01580 259.459 -67.075 600 r 2025-02-07T08:41:43 T01471 262.430 -67.925 600 r 2025-02-07T08:42:15 T01366 265.631 -68.774 600 r 2025-02-07T08:42:28 T04140 172.800 -51.792 600 r 2025-02-07T08:42:38 T03797 171.429 -53.491 600 r 2025-02-07T08:43:16 T03966 170.526 -52.642 600 r 2025-02-07T08:43:23 T04139 170.743 -51.792 600 r 2025-02-07T08:44:25 T04315 169.888 -50.943 600 r 2025-02-07T08:45:22 T05437 170.816 -45.849 600 r 2025-02-07T08:45:45 T04676 168.261 -49.245 600 r 2025-02-07T08:46:24 T04493 167.072 -50.094 600 r 2025-02-07T08:46:37 T05634 170.050 -45.000 600 r 2025-02-07T08:46:46 T04675 166.304 -49.245 600 r 2025-02-07T08:47:17 T05048 164.842 -47.547 600 r 2025-02-07T08:47:25 T06243 167.885 -42.453 600 r 2025-02-07T08:47:50 T05239 164.145 -46.698 600 r 2025-02-07T08:48:05 T06452 167.204 -41.604 600 r 2025-02-07T08:48:08 T06242 166.154 -42.453 600 r 2025-02-07T08:48:46 T05433 163.469 -45.849 600 r 2025-02-07T08:48:54 T05831 163.960 -44.151 600 r 2025-02-07T08:49:55 T05630 162.814 -45.000 600 r 2025-02-07T08:50:53 T06663 165.634 -40.755 600 r 2025-02-07T08:51:14 T06034 163.317 -43.302 600 r 2025-02-07T08:51:55 T05830 162.178 -44.151 600 r 2025-02-07T08:52:14 T07095 166.027 -39.057 600 r 2025-02-07T08:52:16 T06877 165.000 -39.906 600 r 2025-02-07T08:52:46 T06662 163.944 -40.755 600 r 2025-02-07T08:53:03 T06033 161.561 -43.302 600 r 2025-02-07T08:53:20 T07094 164.384 -39.057 600 r 2025-02-07T08:53:37 T06449 162.085 -41.604 600 r 2025-02-07T08:53:39 T07314 164.525 -38.208 600 r 2025-02-07T08:54:15 T06239 160.962 -42.453 600 r 2025-02-07T08:54:23 T07536 163.929 -37.358 600 r 2025-02-07T08:55:24 T06448 160.379 -41.604 600 r 2025-02-07T08:56:24 T06875 161.667 -39.906 600 r 2025-02-07T08:56:44 T07761 164.071 -36.509 600 r 2025-02-07T08:57:25 T07092 161.096 -39.057 600 r 2025-02-07T08:57:46 T06874 160.000 -39.906 600 r 2025-02-07T08:57:51 T07312 161.267 -38.208 600 r 2025-02-07T08:58:16 T07760 162.478 -36.509 600 r 2025-02-07T08:58:40 T07987 162.632 -35.660 600 r 2025-02-07T08:58:55 T07091 159.452 -39.057 600 r 2025-02-07T08:59:09 T07534 160.714 -37.358 600 r 2025-02-07T08:59:10 T07311 159.638 -38.208 600 r 2025-02-07T08:59:44 T07759 160.885 -36.509 600 r 2025-02-07T08:59:52 T08216 162.078 -34.811 600 r 2025-02-07T09:00:52 T07986 161.053 -35.660 600 r 2025-02-07T09:02:02 T08448 162.232 -33.962 600 r 2025-02-07T09:02:13 T07533 159.107 -37.358 600 r 2025-02-07T09:02:55 T08682 162.383 -33.113 600 r 2025-02-07T09:03:17 T07758 159.292 -36.509 600 r 2025-02-07T09:03:27 T07985 159.474 -35.660 600 r 2025-02-07T09:03:46 T08447 160.687 -33.962 600 r 2025-02-07T09:04:18 T08681 160.851 -33.113 600 r 2025-02-07T09:04:24 T07757 157.699 -36.509 600 r 2025-02-07T09:04:37 T07984 157.895 -35.660 600 r 2025-02-07T09:04:42 T08917 160.336 -32.264 600 r 2025-02-07T09:05:16 T08680 159.319 -33.113 600 r 2025-02-07T09:05:22 T09156 160.500 -31.415 600 r 2025-02-07T09:06:21 T08213 157.403 -34.811 600 r 2025-02-07T09:07:32 T09397 160.661 -30.566 600 r 2025-02-07T09:07:42 T10131 159.677 -28.019 600 r 2025-02-07T09:08:24 T08916 158.824 -32.264 600 r 2025-02-07T09:08:46 T10630 158.571 -26.321 600 r 2025-02-07T09:09:05 T09884 159.512 -28.868 600 r 2025-02-07T09:09:19 T09155 159.000 -31.415 600 r 2025-02-07T09:09:53 T10379 158.400 -27.170 600 r 2025-02-07T09:09:56 T09639 159.344 -29.717 600 r 2025-02-07T09:10:12 T09396 159.174 -30.566 600 r 2025-02-07T09:10:14 T08444 156.052 -33.962 600 r 2025-02-07T09:10:45 T11391 156.887 -23.774 600 r 2025-02-07T09:10:52 T10130 158.226 -28.019 600 r 2025-02-07T09:11:51 T08678 156.255 -33.113 600 r 2025-02-07T09:13:11 T11648 156.279 -22.925 600 r 2025-02-07T09:13:53 T11135 156.706 -24.623 300 r 2025-02-07T09:14:15 T09883 158.049 -28.868 600 r 2025-02-07T09:14:41 T10629 157.143 -26.321 600 r 2025-02-07T09:14:49 T09154 157.500 -31.415 800 r 2025-02-07T09:15:21 T10881 156.522 -25.472 500 r 2025-02-07T09:15:33 T09638 157.869 -29.717 800 r 2025-02-07T09:15:40 T09395 157.686 -30.566 800 r 2025-02-07T09:15:45 T08914 155.798 -32.264 800 r 2025-02-07T09:16:14 T11390 155.486 -23.774 800 r 2025-02-07T09:16:20 T11906 155.077 -22.075 700 r 2025-02-07T09:17:21 T12428 154.677 -20.377 700 r 2025-02-07T09:18:41 T09880 153.659 -28.868 600 r 2025-02-08T00:41:46 T10626 152.857 -26.321 600 r 2025-02-08T00:43:24 T09636 154.918 -29.717 600 r 2025-02-08T00:45:12 T11132 152.471 -24.623 600 r 2025-02-08T00:45:19 T12425 150.570 -20.377 600 r 2025-02-08T00:46:07 T11645 152.093 -22.925 600 r 2025-02-08T00:46:30 T12164 151.724 -21.226 600 r 2025-02-08T00:47:17 T11904 152.308 -22.075 600 r 2025-02-08T00:48:08 T10376 154.080 -27.170 600 r 2025-02-08T00:48:18 T12689 151.364 -19.528 600 r 2025-02-08T00:48:54 T08915 157.311 -32.264 600 r 2025-02-08T00:50:48 T12954 151.579 -18.679 600 r 2025-02-08T00:51:48 T09394 156.198 -30.566 600 r 2025-02-08T00:52:05 T12165 153.103 -21.226 600 r 2025-02-08T00:52:53 T11905 153.692 -22.075 600 r 2025-02-08T00:53:44 T12690 152.727 -19.528 600 r 2025-02-08T00:54:26 T11134 155.294 -24.623 600 r 2025-02-08T00:55:05 T13221 152.360 -17.830 600 r 2025-02-08T00:56:19 T12955 152.932 -18.679 600 r 2025-02-08T00:57:28 T12688 150.000 -19.528 600 r 2025-02-08T03:38:19 T13220 151.011 -17.830 600 r 2025-02-08T03:38:22 T11903 150.923 -22.075 600 r 2025-02-08T03:42:15 T12426 151.939 -20.377 600 r 2025-02-08T03:42:18 T11387 151.284 -23.774 600 r 2025-02-08T03:43:58 T12427 153.308 -20.377 600 r 2025-02-08T03:44:08 T11388 152.685 -23.774 600 r 2025-02-08T03:44:37 T10878 152.253 -25.472 600 r 2025-02-08T03:48:03 T12166 154.483 -21.226 300 r 2025-02-08T03:48:25 T11133 153.882 -24.623 600 r 2025-02-08T03:50:12 T10375 152.640 -27.170 600 r 2025-02-08T03:53:43 T11647 154.884 -22.925 600 r 2025-02-08T03:53:57 T10127 153.871 -28.019 600 r 2025-02-08T04:00:44 T10377 155.520 -27.170 600 r 2025-02-08T04:13:24 T09393 154.711 -30.566 600 r 2025-02-08T04:19:11 T09153 156.000 -31.415 600 r 2025-02-08T04:24:31 T09637 156.393 -29.717 600 r 2025-02-08T04:35:51 ------ Detailed photometry and transient search analyses are underway. The 7-Dimensional Telescope (7DT), located in Chile, is a multi-telescope system designed to detect optical counterparts of gravitational wave (GW) sources and conduct the 7-Dimensional Sky Survey (7DS) of the Southern Hemisphere. When fully completed, 7DT will consist of 20 wide-field telescopes equipped with 40 medium-bandwidth (~25nm) filters along with a suite of broad-band filters. Currently, a partially constructed 7DT with 13 telescopes, 20 medium-band filters, and u, g, r, i, z filters is operational. Further information about 7DT is available at https://7ds.snu.ac.kr/ and http://gwuniverse.snu.ac.kr/. The Gravitational-wave EM Counterpart Korean Observatory (GECKO) is a global network of 0.5m to 1m class telescopes, including 7DT, dedicated to the search for electromagnetic counterparts of GW events (Im et al. 2023, Proceedings of IAU Symp. Vol. 363, pp. 207; Paek et al. 2024, ApJ 960, 113). Additionally, KMTNet, operated by the Korea Astronomy and Space Science Institute (KASI), contributes to GW follow-up observations. We thank the KMTNet operators for their support in conducting KMTNet observations and express our gratitude to the ObsTech staff at the El Sauce Observatory for their assistance with 7DT observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/39241. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37250] GRB 250205A: 1.3m DFOT optical upper limit
by GCN Circulars 08 Feb '25

08 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39240 SUBJECT: GRB 250205A: 1.3m DFOT optical upper limit DATE: 25/02/08 17:27:46 GMT FROM: ANSHIKA GUPTA at ARIES <anshika05180(a)gmail.com> Anshika Gupta, Amit K. Ror, Kuntal Misra and Shashi B. Pandey (ARIES) report: We observed the field of GRB 250205A detected by SVOM/ECLAIRs (Saccardi et al. 2025, GCN 39154) with the 1.3m Devasthal Fast Optical Telescope (DFOT), located at the Devasthal Observatory of the Aryabhatta Research Institute of Observational Sciences (ARIES), India. The observations were started on 2025-02-06 at 17:00:56 UT, i.e., ~ 0.81 days after the SVOM trigger. We have taken multiple frames with an exposure time of 300 s in the R filter. We stacked the images after the alignment. We could not detect the optical emission in our stacked image within the error box of SVOM telescope (Palmerio et al. 2025, GCN 39159) and Swift-XRT (Kennea et al. 2025, GCN 39161). We obtain the following 3-sigma upper limit in the stacked image: Date Start_UT T_start-T0 (days) Filter Exp time (s) Magnitude ============================================================ 2025-02-06 17:00:56 ~0.81 R 300s*12 > 22.0 The non-detection of the burst is consistent with the GCN reported by Gompertz et al. GCN 39156, 39158; Schneider et al. GCN 39157; Palmerio et al. GCN 39159; de Ugarte Postigo et al. GCN 39160; Watson et al. GCN 39162; Breeveld et al. GCN 39168; Busmann et al. GCN 39169; Ferro et al. GCN 39170. The magnitude is not corrected for the Galactic extinction in the direction of the burst. Photometric calibration is performed using the standard stars from the USNO-B1.0 catalogue. This circular may be cited. View this GCN Circular online at https://gcn.nasa.gov/circulars/39240. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37249] GRB 250206A: Tiled Swift observations
by GCN Circulars 08 Feb '25

08 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39239 SUBJECT: GRB 250206A: Tiled Swift observations DATE: 25/02/08 16:58:30 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> P. A. Evans (U. Leicester) reports on behalf of the Swift team: Swift has initiated a series of observations, tiled on the sky, of the Fermi/LAT GRB 250206A. Automated analysis of the XRT data will be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00132 Any uncatalogued X-ray sources detected in this analysis will be reported on this website and via GCN COUNTERPART notices. The probability of finding serendipitous sources, unrelated to the Fermi/LAT event is high: any X-ray source considered to be a probable afterglow candidate will be reported via a GCN Circular after manual consideration. Details of the XRT automated analysis methods are detailed in Evans et al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8). This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/39239. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37248] LIGO/Virgo/KAGRA S250118az: Updated Sky localization
by GCN Circulars 08 Feb '25

08 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39238 SUBJECT: LIGO/Virgo/KAGRA S250118az: Updated Sky localization DATE: 25/02/08 16:27:45 GMT FROM: Will Farr <will.farr(a)stonybrook.edu> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S250118az (GCN Circular 38973). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S250118az For the Bilby.offline0.multiorder.fits,0 sky map, the 90% credible region is 601 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 918 +/- 401 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380 View this GCN Circular online at https://gcn.nasa.gov/circulars/39238. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37247] LIGO/Virgo/KAGRA S250208ad: Updated Sky localization
by GCN Circulars 08 Feb '25

08 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39237 SUBJECT: LIGO/Virgo/KAGRA S250208ad: Updated Sky localization DATE: 25/02/08 15:45:05 GMT FROM: Will Farr <will.farr(a)stonybrook.edu> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S250208ad (GCN Circular 39223). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S250208ad For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 1128 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 4871 +/- 1417 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380 View this GCN Circular online at https://gcn.nasa.gov/circulars/39237. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37246] GRB 250206A: EIRSAT-1 GMOD Detection
by GCN Circulars 08 Feb '25

08 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39236 SUBJECT: GRB 250206A: EIRSAT-1 GMOD Detection DATE: 25/02/08 15:43:17 GMT FROM: Caimin McKenna at University College Dublin <caimin.mckenna(a)ucdconnect.ie> D. Murphy, C. McKenna, C. de Barra, A. Ulyanov, P. McDermott, M. Doyle, R. Dunwoody, J. Mangan, G. Finneran, G. Corcoran, L. Cotter, A. Empey, J. Fisher, F. Gibson Kiely, J. Thompson, D. McKeown, A. Martin-Carrillo, L. Hanlon, S. McBreen, on behalf of the EIRSAT-1 team: EIRSAT-1 reports the detection of the long gamma-ray burst GRB250206A by the Gamma-ray Module (GMOD) instrument, which was also detected by Fermi GBM (GCN [39172](https://gcn.nasa.gov/circulars/39172)). The detection was made starting at 2025-02-06 19:51:22.4 UTC. The GMOD light curve for GRB250206A with 1.2s binning shows a long burst with two pulses, separated by 7.2 seconds, consistent with that seen by NASA Fermi-GBM. The 3rd softer pulse is not detected by GMOD. The spacecraft location at the time of detection was 5.095 N, 35.194 E at an altitude of 439.8 km. The GMOD light curve for this event can be found here: https://grb.eirsat1.ie/250206A/250206A_LC_onboard_preliminary.png EIRSAT-1 is Ireland’s first satellite (Doyle et al. Proceedings of the 4th SSEA, 2022). It is a 2U CubeSat and carries onboard a number of experiments including the Gamma-Ray Module (GMOD), a novel, compact, gamma-ray detector (Murphy et al, Experimental Astronomy, 53, 961–990, 2022). GMOD consists of a 25 mm × 25 mm × 40 mm Cerium Bromide scintillator coupled to SiPMs and is designed to detect gamma-ray bursts in the ~ 60 keV - 1.5 MeV range. EIRSAT-1 was developed in University College Dublin with support from ESA’s Fly Your Satellite! programme and was launched on 1st December 2023. View this GCN Circular online at https://gcn.nasa.gov/circulars/39236. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37245] LIGO/Virgo/KAGRA S250206dm: (Update-7) NED Galaxies in the Localization Volume
by GCN Circulars 08 Feb '25

08 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39235 SUBJECT: LIGO/Virgo/KAGRA S250206dm: (Update-7) NED Galaxies in the Localization Volume DATE: 25/02/08 14:56:18 GMT FROM: David Cook at Caltech/IPAC-NED <dcook(a)ipac.caltech.edu> David O. Cook (Caltech/IPAC), Rick Ebert (Caltech/IPAC), George Helou (Caltech/IPAC), Joseph M. Mazzarella (Caltech/IPAC), Marion Schmitz (Caltech/IPAC), and Leo Singer (NASA/GSFC) On behalf of the NASA/IPAC Extragalactic Database (NED) Team. We spatially cross-matched the LVK S250206dm-7-Update sky localization with the NED Local Volume Sample (NED-LVS; Cook et al. 2023), which is a subset of NED with a redshift or redshift-independent distance less than 1000 Mpc. We find 20861 galaxies within the 90% containment volume, and we list here the top 20 galaxies sorted by the joint probability of the 3D localization and the WISE W1 luminosity (an observable proxy for stellar mass). For the full or top 20 list of galaxies in the 90% volume go either to the NED Gravitational Wave Followup service at https://ned.ipac.caltech.edu/uri/NED::GWF/ or click on the following links: Full List Download: https://ned.ipac.caltech.edu/uri/NED::GWFglist/fits/S250206dm/7 Top 20 List Download: https://ned.ipac.caltech.edu/uri/NED::GWFglist/fits/S250206dm/7/20 The NED-GWF service provides downloadable galaxy lists and visualizations for candidate host galaxies. For each GW alert, these products are automatically generated and made available within minutes to expedite efficient electromagnetic follow-up observations. The NED top 20 list is sorted by the joint probability of the 3D localization and the WISE W1 luminosity, but users can sort on additional pre-computed prioritization metrics (star formation rate, P_3D * P_SFR; and specific star formation rate, P_3D * P_sSFR; etc.) which are available via downloading the entire galaxy list inside the event's probability volume. | objname| ra| dec|objtype| DistMpc|DistMpc_unc| m_NUV|m_NUV_unc| m_Ks| m_Ks_unc| m_W1| m_W1_unc| P_3D|P_3D_LumW1| |-------------------------|--------------|--------------|-------|-----------|-----------|-------|---------|------------|------------|------------|------------|--------|----------| |WISEA J022843.33+542030.5| 37.18021| 54.34178| G| 408.50| null| null| null| 13.098| 0.150| 9.250| 0.006|2.36e-06| 4.22e-09| |WISEA J022348.88+533854.6| 35.95371| 53.64847| G| 361.18| null| null| null| 12.653| 0.121| 10.626| 0.007|2.93e-06| 1.14e-09| |WISEA J023404.21+543420.9| 38.51758| 54.57247| G| 387.94| 0.60| null| null| 11.605| 0.091| 11.228| 0.010|2.73e-06| 7.21e-10| |WISEA J022610.54+530728.2| 36.54379| 53.12453| G| 369.10| null| null| null| 13.505| 0.153| 11.533| 0.008|4.03e-06| 7.10e-10| |WISEA J024025.00+541511.8| 40.10413| 54.25331| G| 377.15| null| null| null| 13.153| 0.114| 11.550| 0.010|2.94e-06| 5.49e-10| |WISEA J024516.51+542758.5| 41.31871| 54.46631| G| 365.18| null| null| null| 12.190| 0.129| 10.967| 0.007|1.78e-06| 5.48e-10| |WISEA J022200.27+503737.1| 35.50117| 50.62697| G| 288.27| null| null| null| 12.566| 0.105| 9.223| 0.006|5.70e-07| 5.36e-10| |WISEA J023155.31+513044.0| 37.98038| 51.51228| G| 322.72| null| null| null| 13.525| 0.153| 10.101| 0.006|8.93e-07| 4.56e-10| |WISEA J023620.33+544551.7| 39.08458| 54.76433| G| 260.69| 0.40| null| null| 11.288| 0.099| 10.411| 0.006|1.75e-06| 4.45e-10| |WISEA J023712.75+540728.3| 39.30317| 54.12464| G| 281.88| null| null| null| 12.709| 0.114| 11.242| 0.006|3.18e-06| 4.38e-10| |WISEA J022430.81+525101.6| 36.12842| 52.85050| G| 400.04| null| null| null| 12.694| 0.141| 11.911| 0.010|3.00e-06| 4.37e-10| |WISEA J161708.84-674024.7| 244.28700| -67.67294| G| 314.35| null| null| null| 12.878| 0.112| 9.322| 0.006|4.41e-07| 4.23e-10| |WISEA J022614.61+524507.6| 36.56092| 52.75206| G| 429.82| null| null| null| 13.099| 0.140| 11.893| 0.009|2.42e-06| 4.21e-10| |WISEA J024335.91+531732.8| 40.89963| 53.29250| G| 351.10| null| null| null| 13.087| 0.139| 11.487| 0.011|2.44e-06| 4.19e-10| |WISEA J021942.98+525320.0| 34.92904| 52.88886| G| 471.43| null| null| null| 12.998| 0.153| 11.105| 0.012|9.81e-07| 4.14e-10| |WISEA J022523.45+533416.2| 36.34758| 53.57089| G| 544.42| null| null| null| 12.873| 0.115| 10.515| 0.006|3.76e-07| 3.68e-10| |WISEA J022425.11+524210.8| 36.10462| 52.70289| G| 303.57| null| null| null| 11.882| 0.114| 11.585| 0.019|3.24e-06| 3.67e-10| |WISEA J022226.96+515125.6| 35.61233| 51.85711| G| 338.33| null| null| null| 13.057| 0.131| 11.350| 0.009|2.10e-06| 3.67e-10| |WISEA J022553.94+515215.4| 36.47396| 51.87139| G| 340.02| null| null| null| 12.716| 0.089| 11.376| 0.007|1.97e-06| 3.42e-10| |WISEA J022458.67+520149.0| 36.24458| 52.03025| G| 255.83| 0.86| null| null| 10.779| 0.064| 10.693| 0.007|1.86e-06| 3.40e-10| Table 1: Top 20 galaxies in NED-LVS that fall in the 90% probability volume for S250206dm sorted by the joint probability of 3D position and WISE W1 luminosity (P_3D * P_LumW1). Galaxy is the NED preferred name. RA and Dec are the Equatorial coordinates in degrees (J2000). Objtype is the object type of the galaxy candidate. Distance is the distance to the galaxy in Mpc. m_NUV and mErr_NUV are the apparent magnitude and error from GALEX. m_Ks and mErr_Ks are the apparent magnitude and error from 2MASS. m_W1 and mErr_W1 are the apparent magnitude and error from AllWISE. P_3D is the probability that the galaxy is in the volume given the distance of GW event. P_3D_LumW1 is the joint probability within the volume weighted by the WISE1 luminosity of the galaxy (P_3D * P_LumW1). View this GCN Circular online at https://gcn.nasa.gov/circulars/39235. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37244] LIGO/Virgo/KAGRA S250206dm: NEWFIRM NIR Observations
by GCN Circulars 08 Feb '25

08 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39234 SUBJECT: LIGO/Virgo/KAGRA S250206dm: NEWFIRM NIR Observations DATE: 25/02/08 14:29:23 GMT FROM: David Coulter at STScI <dcoulter(a)ucsc.edu> D. A. Coulter (STScI), C. D. Kilpatrick (Northwestern), P. Macias (UCSC), R. J. Foley (UCSC), K. W. Davis (UCSC), A. Villar (Harvard) reports on behalf of the Gravity Collective [1, 2]: We searched the localization region of the probable NSBH merger candidate, S250206dm (LVK Collaboration, [GCN 39175](https://gcn.nasa.gov/circulars/39175)), with the ~0.22 square degree field-of-view near IR imager NEWFIRM currently mounted on the Blanco 4-m telescope at CTIO. We observed the entire 0.43 deg confidence region reported by the IceCube Collaboration ([GCN 39176](https://gcn.nasa.gov/circulars/39176)) that overlapped with the GW localization, beginning observations at 2025-02-07 05:47 UTC (+8.3 hours after GW trigger) in J-band. We obtained 3 sequences of 22x5 second co-adds across the neutrino confidence region, with an average depth of J ~ 22 AB mag. Data were processed using standard procedures in photpipe [3], and we performed image subtraction across each field using templates constructed from VIRCAM J-band images with limiting magnitudes of J ~ 19 AB mag. After vetting sources of transient emission as being unassociated with variable stars, minor planets, and known transients in each surveyed field, we concluded that there are no likely sources of transient emission in the NEWFIRM imaging. [1] Kilpatrick, C. D. et al. 2021 [2] Coulter, D. A., et al. 2024 [3] Rest, A. et al. 2005 View this GCN Circular online at https://gcn.nasa.gov/circulars/39234. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37243] GRB 250206A: Fermi-LAT detection
by GCN Circulars 08 Feb '25

08 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39233 SUBJECT: GRB 250206A: Fermi-LAT detection DATE: 25/02/08 13:50:51 GMT FROM: Rahul Gupta at NASA GSFC <rahul.gupta(a)nasa.gov> R. Gupta (NASA GSFC), S. Lopez (CNRS / IN2P3), and A. Holzmann Airasca (UniTrento and INFN Bari) on behalf of the Fermi-LAT Collaboration: On February 06, 2025, Fermi-LAT detected high-energy emission from GRB 250206A, which was also detected by Fermi-GBM (trigger 760564296 / 250206827, GCN 39172). The best LAT on-ground location is found to be: RA, Dec = 225.31, -62.26 (J2000) with an error radius of 0.56 deg (90 % containment, statistical error only). This was 33 deg from the LAT boresight at the time of the GBM trigger (T0 = 19:51:31.93 UT). The data from the Fermi-LAT shows a significant increase in the event rate that is spatially and temporally correlated with the GBM emission with high significance. The photon flux above 100 MeV in the time interval 0 - 90 s after the GBM trigger is (2.1 ± 0.7) E-5 ph/cm2/s. The estimated photon index above 100 MeV is 2.1 ± 0.3. The highest-energy photon is a 1.4 GeV event which is observed ~ 16 seconds after the GBM trigger. A Swift ToO has been approved for this burst. The Fermi-LAT point of contact for this burst is Rahul Gupta (rahulbhu.c157(a)gmail.com). The Fermi-LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden. View this GCN Circular online at https://gcn.nasa.gov/circulars/39233. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37242] GRB 250207B: Swift-XRT observations
by GCN Circulars 08 Feb '25

08 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39232 SUBJECT: GRB 250207B: Swift-XRT observations DATE: 25/02/08 13:22:06 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAR), T. Sbarrato (INAF-OAB), J.A. Kennea (PSU), D.N. Burrows (PSU), M. A. Williams (PSU), A.P. Beardmore (U. Leicester), J.P. Osborne (U. Leicester) and P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team: Swift-XRT has performed follow-up observations of the MAXI-detected burst GRB 250207B in a series of observations tiled on the sky. The total exposure time is 1.5 ks, distributed over 6 tiles; the maximum exposure at a single sky location in the tiling was 540 s. The data were collected between T0+51.2 ks and T0+53.6 ks, and are entirely in Photon Counting (PC) mode. No X-ray sources have been detected. The 3-sigma upper limit in the field (not including the regions where the tiles overlap) ranges from ~0.0e+00 to ~5.5e-01 ct s^-1, corresponding to a 0.3-10 keV observed flux of 0.0e+00 to 2.2e-11 erg cm^-2 s^-1 (assuming a typical GRB spectrum). The results of the XRT-team automatic analysis of the tiled XRT observations, including a position-specific upper limit calculator, are available at https://www.swift.ac.uk/xrt_products/TILED_GRB00131. This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/39232. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37241] LIGO/Virgo/KAGRA S250206dm: Updated Sky localization and EM Bright Classification
by GCN Circulars 08 Feb '25

08 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39231 SUBJECT: LIGO/Virgo/KAGRA S250206dm: Updated Sky localization and EM Bright Classification DATE: 25/02/08 11:14:31 GMT FROM: Divyajyoti NLN <divyajyoti.nln(a)ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S250206dm (GCN Circular 39184). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline1.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S250206dm Based on posterior support from parameter estimation [1], under the assumption that the candidate S250206dm is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is >99%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is 13%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 35%. For the Bilby.offline1.multiorder.fits,0 sky map, the 90% credible region is 547 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 373 +/- 104 Mpc (a posteriori mean +/- standard deviation). At the time of the candidate, the Virgo detector was being brought online and was not in observing mode. However, it was determined that the Virgo detector was sufficiently sensitive to inform our estimate of the sky localization. Investigations are ongoing to understand how the operational state of Virgo at the time of the event impacts this analysis. The estimated sky localization may change based on these studies, but this skymap represents our best understanding of the event at this time. For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380 [2] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe View this GCN Circular online at https://gcn.nasa.gov/circulars/39231. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37240] IceCube-250203A: No transient candidates from the Zwicky Transient Facility
by GCN Circulars 08 Feb '25

08 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39230 SUBJECT: IceCube-250203A: No transient candidates from the Zwicky Transient Facility DATE: 25/02/08 08:28:20 GMT FROM: akshay.eranhalodi(a)desy.de Akshay Eranhalodi (DESY), Robert Stein (JSI), Sven Weimann (Ruhr University Bochum), Jannis Necker (DESY) and Anna Franckowiak (Ruhr University Bochum) report: On behalf of the Zwicky Transient Facility (ZTF) and Global Relay of Observatories Watching Transients Happen (GROWTH) collaborations: As part of the ZTF neutrino follow up program (Stein et al. 2023), we observed the localization region of the neutrino event IceCube-250203A (Zegarelli et. al, GCN 39132) with the Palomar 48-inch telescope, equipped with the 47 square degree ZTF camera (Bellm et al. 2019, Graham et al. 2019). We started observations in the g- and r-band beginning at 2025-02-04 12:30 UTC, approximately 32.5 hours after event time. We covered 96.0% (0.9 sq deg) of the reported localization region. This estimate accounts for chip gaps. Each exposure was 300s with a typical depth of 21.0 mag. The images were processed in real-time through the ZTF reduction and image subtraction pipelines at IPAC to search for potential counterparts (Masci et al. 2019). AMPEL (Nordin et al. 2019, Stein et al. 2021) was used to search the alerts database for candidates. We reject stellar sources (Tachibana and Miller 2018) and moving objects, and apply machine learning algorithms (Mahabal et al. 2019) . No candidate counterparts were detected. Observations of this localisation will continue over the coming days as part of our standard monitoring cadence for neutrino alerts (Stein et al. 2023). Based on observations obtained with the Samuel Oschin Telescope 48-inch and the 60-inch Telescope at the Palomar Observatory as part of the Zwicky Transient Facility project. ZTF is supported by the National Science Foundation under Grant No. AST-2034437 and a collaboration including Caltech, IPAC, the Oskar Klein Center at Stockholm University, the University of Maryland, University of California, Berkeley , the University of Wisconsin at Milwaukee, University of Warwick, Ruhr University Bochum, Cornell University, Northwestern University and Drexel University. Operations are conducted by COO, IPAC, and UW. GROWTH acknowledges generous support of the NSF under PIRE Grant No 1545949. Alert distribution service provided by DIRAC@UW (Patterson et al. 2019). Alert database searches are done by AMPEL (Nordin et al. 2019). Alert filtering is performed with the nuztf (Stein et al. 2021, https://github.com/desy-multimessenger/nuztf ). View this GCN Circular online at https://gcn.nasa.gov/circulars/39230. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37239] LIGO/Virgo/KAGRA S250206dm: Spectroscopic Classification of AT2025bay and AT2025baz with Keck I/LRIS
by GCN Circulars 08 Feb '25

08 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39229 SUBJECT: LIGO/Virgo/KAGRA S250206dm: Spectroscopic Classification of AT2025bay and AT2025baz with Keck I/LRIS DATE: 25/02/08 07:55:32 GMT FROM: Viraj Karambelkar at Indian Inst of Tech,Bombay <karambelkarvraj21197(a)gmail.com> Viraj Karambelkar (Caltech), Tomás Ahumada (Caltech), Mansi Kasliwal (Caltech) report on behalf of the ZTF and GROWTH collaborations: We report optical spectroscopy of two counterpart candidates reported by the Zwicky Transient Facility, AT 2025bay, AT 2025baz (GCN #39228) in the localization region of LIGO/Virgo S200206dm (LVC, GCN #39175,39184). We used the Low Resolution Imaging Spectrometer (Oke et al. 1995) on the Keck I telescope, reduced data using the idl package lpipe (Perley 2019) and find: ZTF25aaffyzc / AT2025bay shows broad features matching a Type Ia supernova before maximum at z = 0.19 ZTF25aaffzpx / AT2025baz matches a Cataclysmic Variable in the Milky Way and shows Balmer emission lines at z = 0.0 Thus, AT2025bay and AT2025baz are not related to the gravitational wave event. We are grateful to the Keck Observatory staff, Sherry Yeh and Matthew Wahl, as well as observers, Andrew Howard and Howard Isaacson, for swiftly co-operating with these Target-of-Opportunity observations for rapidly setting targets. View this GCN Circular online at https://gcn.nasa.gov/circulars/39229. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37238] LIGO/Virgo/KAGRA S250206dm: Candidates from the Zwicky Transient Facility
by GCN Circulars 08 Feb '25

08 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39228 SUBJECT: LIGO/Virgo/KAGRA S250206dm: Candidates from the Zwicky Transient Facility DATE: 25/02/08 07:48:41 GMT FROM: Tomas Ahumada Mena at Caltech <tahumada(a)caltech.edu> Tomás Ahumada (Caltech), Viraj Karambelkar (CIT), Eric Bellm (UW), Mansi Kasliwal (CIT), Shreya Anand (Stanford), Robert Stein (JSI/UMD), Theophile du Laz (CIT), Avery Wold (IPAC), Igor Andreoni (UMD), Varun Bhalerao (IITB), Brad Cenko (NASA GSFC/UMD), Michael Coughlin (UMN), David Kaplan (UWM), Leo Singer (NASA GSFC), Jesper Sollerman (OKC) report on behalf of the ZTF and GROWTH collaborations: We observed the localization region of the LVK trigger S250206dm (GCN 39175) with the Palomar 48-inch telescope equipped with the 47 square-degree Zwicky Transient Facility (ZTF) camera (Graham et al., 2019; Bellm et al., 2019). We obtained images in the g- and r-bands of the Bilby map (GCN 39184). We started observations in the g- and r- beginning at 2024-02-08 02:21 UTC, approximately 29 hours after event time (delay due to wet weather at Palomar on the first night). We targeted 52% (1081 sq deg) of the reported localization region with 300s exposures. We queried the ZTF alert stream using Kowalski (Duev et al. 2019) through Fritz (Coughlin et al. 2023) and emgwcave (Karambelkar et al. in prep). We required at least 2 detections separated by at least 15 minutes to select against moving objects. Furthermore, we cross-match our candidates with the Minor Planet Center to flag known asteroids, reject stellar sources (Tachibana and Miller 2018 and using the GAIA catalog), reject AGNs based on WISE colors, and apply machine learning algorithms for classification (Mahabal et al. 2019). We require that no spatially coincident ZTF alerts were issued before the detection time of the LVK trigger. We also ran forced photometry on ZTF images (Masci et al. 2019) and required no detections before the LVK trigger. Two sources were found within the 95% localization region and reported to TNS: id | AT name |ra |dec | mjd| mag |filter| comment ZTF25aaffzpx | AT 2025baz | 02:19:26.60 | +47:32:49.80 | 60714.15932870 | 20.4 | r | hostless ZTF25aaffyzc | AT 2025bay | 00:30:01.17 | +37:10:06.06 | 60714.13770830 | 20.5 | r | no redshift available Based on observations obtained with the Samuel Oschin Telescope 48-inch and the 60-inch Telescope at the Palomar Observatory as part of the Zwicky Transient Facility project. ZTF is supported by the National Science Foundation under Award #2407588 and a partnership including Caltech, USA; Caltech/IPAC, USA; University of Maryland, USA; University of California, Berkeley, USA; University of Wisconsin at Milwaukee, USA; Cornell University, USA; Drexel University, USA; University of North Carolina at Chapel Hill, USA; Institute of Science and Technology, Austria; National Central University, Taiwan; Operations are conducted by Caltech's Optical Observatory (COO) and Caltech/IPAC. GROWTH acknowledges the generous support of the NSF under PIRE Grant No 1545949. Alert database searches are done by AMPEL (Nordin et al. 2019) and Kowalski (Duev et al. 2019). The GROWTH India Telescope (GIT, Kumar et al., 2022) is set up by the Indian Institute of Astrophysics (IIA) and the Indian Institute of Technology Bombay (IITB) with funding from DST-SERB and IUSSTF. Its operations are partially supported by funding from the IIT Bombay alumni batch of 1994. The Fritz and SkyPortal projects acknowledge the generous support of The Gordon and Betty Moore Foundation. View this GCN Circular online at https://gcn.nasa.gov/circulars/39228. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37237] LIGO/Virgo/KAGRA S250206dm: ePESSTO+ classification of AT2025bar
by GCN Circulars 08 Feb '25

08 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39227 SUBJECT: LIGO/Virgo/KAGRA S250206dm: ePESSTO+ classification of AT2025bar DATE: 25/02/08 07:16:28 GMT FROM: James Gillanders at University of Oxford <jhgillanders.astro(a)gmail.com> J. Gillanders (Oxford), D. Magill, M. Fulton (QUB), S. Srivastav (Oxford), T. de Lourenco Pessi (ESO), P. Pessi (Stockholm), D. O’Neill (Warwick), T.-W. Chen (NCU), J. Anderson (ESO), M. Gromadzki (Warsaw), C. Inserra (Cardiff), E. Kankare (Turku), T. Müller Bravo (Trinity), A. Horowicz, O. Yaron, E. Zimmerman (Weizmann), D. Young (QUB). ePESSTO+, the advanced Public ESO Spectroscopic Survey for Transient Objects (Smartt et al., 2015, 2015A&A...579A..40S) observed AT2025bar, the candidate optical counterpart reported by Steeghs et al., (GCN 39215) for the LIGO/Virgo/KAGRA GW event S250206dm (LVK Collaboration, GCN 39175). Our observation was carried out with ESO’s New Technology Telescope (NTT) at La Silla, employing EFOSC2 and Grism #13 (3985-9315A, 18A resolution). Our observation commenced at 2025-02-08 06:06 UTC, corresponding to 1.36 days (or 32.7 hours) after the GW merger event, and consisted of a single 2100s exposure employing a 1.5 arcsec slit. The reduced spectrum closely resembles a type Ia supernova ~a few days pre-maximum light, with a redshift of ~0.17 (determined from template matching with SNID; Blondin & Tonry, 2007, 2007ApJ...666.1024B). Thus, we conclude that AT2025bar is not related to the GW event S250206dm. This classification spectrum (and additional details) will be publicly available within 24 hours from http://www.pessto.org (via WISeREP) and the IAU Transient Name Server, as part of standard ePESSTO+ science operations. View this GCN Circular online at https://gcn.nasa.gov/circulars/39227. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37236] EP-WXT trigger 01709131361 / LIGO/Virgo/KAGRA S250206dm: FTW optical and NIR observations
by GCN Circulars 08 Feb '25

08 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39214 SUBJECT: EP-WXT trigger 01709131361 / LIGO/Virgo/KAGRA S250206dm: FTW optical and NIR observations DATE: 25/02/07 19:58:43 GMT FROM: Malte Busmann at Ludwig-Maximilians-Universität München <m.busmann(a)physik.lmu.de> Malte Busmann (LMU), Daniel Gruen (LMU), Brendan O’Connor (Carnegie Mellon U.) and Antonella Palmese (Carnegie Mellon U.), Julius Gassert (LMU), Lena Schnappinger (LMU), Julian Sommer (LMU), Lei Hu (Carnegie Mellon U.), Franziska Krause (LMU), Elia Enlghard (LMU) and Yajie Zhang (LMU) report: We observed the 90% localization of EP-WXT trigger 01709131361, which lies inside of the 70% localization of S250206dm (LIGO Scientific Collaboration, GCN 39184) with the Three Channel Imager (3KK) at the Fraunhofer-Telescope Wendelstein (FTW) in the r, i and J band simultaneously for 17 x 180 s under suboptimal sky conditions. The observations started at 2025-02-07T17:52:05 UT (2.0 h after the EP-WXT trigger and 20.4 h after the NSBH/BNS merger). We performed difference imaging in the r band with templates from the DESI Legacy Surveys and do not identify any variable optical sources to a 3-sigma depth of r>20.9 AB mag calibrated to the PS1 catalog. Further observations are encouraged. We thank Christoph Ries from the Wendelstein Observatory for obtaining these observations. UPDATE: We do see the flaring star mentioned by Levan et al. (GCN 39218) but initially rejected it. For details see O'Connor et al. (GCN 39219). View this GCN Circular online at https://gcn.nasa.gov/circulars/39214. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37235] LIGO/Virgo/KAGRA S250206dm: COLIBRÍ/DDRAGO Observations of the DDOTI optical candidates
by GCN Circulars 08 Feb '25

08 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39226 SUBJECT: LIGO/Virgo/KAGRA S250206dm: COLIBRÍ/DDRAGO Observations of the DDOTI optical candidates DATE: 25/02/08 06:55:31 GMT FROM: F. Fortin at IRAP <ffortin.sci.edu(a)gmail.com> Francis Fortin (IRAP), Alan M. Watson (UNAM), Sarah Antier (OCA), Stéphane Basa (UAR Pytheas), William H. Lee (UNAM), Dalya Akl (AUS), Camila Angulo (UNAM), Jean-Luc Atteia (IRAP), Rosa L. Becerra (Università degli Studi di Roma Tor Vergata), Nathaniel R. Butler (ASU), Damien Dornic (CPPM), Jean-Grégoire Ducoin (CPPM), Noémie Globus (UNAM), Francesco Magnani (CPPM), Margarita Pereyra (UNAM), and Benjamin Schneider (LAM) report: We imaged the fields of the two candidates reported by the DDOTI team (Becerra et al., GCN Circ. 39208) as a possible optical counterpart of the GW transient S250206dm (LVK Collaboration, GCN Circ. 39175, GCN Circ. 39184) with the DDRAGO wide-field imager on the COLIBRÍ telescope at the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir in Mexico. We observed source 1 from 2025-02-08 04:48 to 05:20, obtaining 480 seconds of exposure in each of the g and r filters. At the position of the source reported by Becerra et al., we do not detect a source to 3-sigma limiting magnitudes of: g > 22.0 r > 22.1 We observed source 2 from 2025-02-08 05:39 to 06:09, again obtaining 480 seconds of exposure in each of the g and r filters. At the position of the source reported by Becerra et al., we do not detect a source to 3-sigma limiting magnitudes of: g > 22.5 r > 22.6 The data were reduced and stacked using custom software and then calibrated against the PS1 catalog and analysed using STDPipe (Karpov 2021). Our magnitude limits are not corrected for Galactic extinction. Our limits at about 32 hours after the GW event are significantly fainter than the detections reported by the DDOTI team. We warmly thank the COLIBRÍ and DDRAGO engineering teams and the staff of the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir. View this GCN Circular online at https://gcn.nasa.gov/circulars/39226. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37234] GRB 250208A: Fermi GBM Final Real-time Localization
by GCN Circulars 08 Feb '25

08 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39225 SUBJECT: GRB 250208A: Fermi GBM Final Real-time Localization DATE: 25/02/08 05:14:47 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply(a)GIOC.nsstc.nasa.gov> The Fermi GBM team reports the detection of a likely LONG GRB At 05:03:59 UT on 8 Feb 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250208A (trigger 760683844.557836 / 250208211). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 191.4, Dec = -11.8 (J2000 degrees, equivalent to J2000 12h 45m, -11d 48'), with a statistical uncertainty of 6.8 degrees. The angle from the Fermi LAT boresight is 39.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250208211/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250208211/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250208211/… View this GCN Circular online at https://gcn.nasa.gov/circulars/39225. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37233] EP250207a: EP-WXT detection and XRT follow-up observation
by GCN Circulars 08 Feb '25

08 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39224 SUBJECT: EP250207a: EP-WXT detection and XRT follow-up observation DATE: 25/02/08 05:14:40 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> D. Y. Li, M. J. Liu, J. An, S.Y. Fu, S. Q. Jiang, X. Liu, D. Xu, Z. P. Zhu, M. H. Zhang (NAOC, CAS), Q. C. Shui (IHEP, CAS), W. D. Zhang (NAOC, CAS) report on behalf of the Einstein Probe team: We report on the detection of an X-ray transient by EP-WXT, designated EP250207a, which triggered the on-board processing unit at 2025-02-07T15:51:17 (trigger ID: 01709131361). The WXT position of the source is R.A. = 356.902 deg, DEC = 27.027 deg (J2000) with an uncertainty of 2.2 arcmin in radius (90% C.L. statistical and systematic). The average 0.5-4 keV spectrum can be fitted with an apec model with a temperature of 3.1 (-1.2, +5.9) keV. No significant absorption is required during the spectral fitting. The derived average 0.5-4 keV flux is 2.9 (-0.7, +0.9) x10^-10 erg/s/cm2. The uncertainties are at the 90% confidence level for the above parameters. We performed a target of opportunity observation with Swift. The Swift XRT observation began at 2025-02-07T17:59:50 (UTC) with an exposure time of 1716 seconds in the Photon Counting mode, about 2 hours after the burst detected by EP-WXT. A bright X-ray source, which is spatially consistent with the low-mass star 2MASS J23473680+2702068 (distance ~ 21.3 pc), was detected within the WXT error circle. The X-ray spectrum can be fitted with two apec components, with temperature of 0.75 (-0.3, +0.2) keV, and 2.6 (-0.6, +1.3) keV, respevtively. No significant absorption is required during the spectral fitting. The derived 0.3-10 keV flux is 9.2 (-1.0, +1.1)x10^-12 erg/s/cm2, corresponding to a luminosity of around 5x10^29 erg/s. We suggest this transient is a stellar flare from this low-mass star. We thank the Neil Gehrels Swift team for making the quick follow-up observation possible. Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). View this GCN Circular online at https://gcn.nasa.gov/circulars/39224. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37232] LIGO/Virgo/KAGRA S250208ad: Identification of a GW compact binary merger candidate
by GCN Circulars 08 Feb '25

08 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39223 SUBJECT: LIGO/Virgo/KAGRA S250208ad: Identification of a GW compact binary merger candidate DATE: 25/02/08 04:34:56 GMT FROM: chl20171(a)outlook.com The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S250208ad during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2025-02-08 03:51:06.789 UTC (GPS time: 1423021884.789). The candidate was found by the CWB [1], CWB BBH [2], GstLAL [3], MBTA [4], PyCBC Live [5], and SPIIR [6] analysis pipelines. S250208ad is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.7e-10 Hz, or about one in 84 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S250208ad After parameter estimation by RapidPE-RIFT [7], the classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [8] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [8] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 31 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 1750 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3453 +/- 1025 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] T. Mishra et al. PRD 105, 083018 (2022) doi:10.1103/PhysRevD.105.083018 [3] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [4] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [5] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [6] Chu et al. PRD 105, 024023 (2022) doi:10.1103/PhysRevD.105.024023 [7] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002 [8] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [9] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013 View this GCN Circular online at https://gcn.nasa.gov/circulars/39223. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37231] LIGO/Virgo/KAGRA S250206dm: MMT galaxy targeted observations
by GCN Circulars 08 Feb '25

08 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39222 SUBJECT: LIGO/Virgo/KAGRA S250206dm: MMT galaxy targeted observations DATE: 25/02/08 01:45:30 GMT FROM: Harsh Kumar at Center for Astrophysics | Harvard & Smithsonian <harshkosli13(a)gmail.com> H. Kumar, E. Berger, A. Villar, D. Hiramatsu, P. K. Blanchard, K. D. Soto, S. K. Yadavalli, M. Hussaini, A. Gagliano, S. Gomez and C. Ransome (Harvard) report: We obtained imaging with Binospec on the 6.5m MMT to search for an optical counterpart to the gravitational wave event S250206dm (GCN #39175, #39184). A series of 120-second r-band images were obtained starting about 5 hours after the GW trigger, targeting Glade+ galaxies (G. Dálya et al. 2021) coincident with the 3D localization (bayestar.fits.gz,1) of the event. We do not detect any new transients near targeted galaxies within the localization volume compared to PS1/3pi images down to ~21.7 mag. A list of observed galaxies is listed below: -------------------------------------- GLADE ID | RA (J2000) | Dec (J2000)| -------------------------------------- 03WFD | 34.07875 | 51.68233 | 01JP0 | 41.07416 | 53.40766 | 01HGY | 37.20916 | 52.92669 | 0650c | 36.18916 | 52.67455 | 048BX | 34.57416 | 51.97930 | 06IPX | 34.02416 | 51.86102 | 001TW | 41.78666 | 53.72905 | 1XD7Y | 15.89166 | 44.00536 | 065O8 | 36.20291 | 52.59722 | 065O6 | 36.29791 | 52.25575 | 0I29U | 41.80708 | 53.73738 | 00BDI | 42.80416 | 54.14144 | 01JNX | 36.19875 | 51.99944 | 00PCL | 43.07583 | 53.98008 | -------------------------------------- We thank Ryan Howie, Ben Weiner, and MMT staff for the rapid execution of these observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/39222. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37230] GRB 250207A: Swift-XRT refined Analysis
by GCN Circulars 08 Feb '25

08 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39221 SUBJECT: GRB 250207A: Swift-XRT refined Analysis DATE: 25/02/08 01:34:17 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> A. Melandri (INAF-OAR), T. Sbarrato (INAF-OAB), D.N. Burrows (PSU), M. A. Williams (PSU), S. Dichiara (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), P. D'Avanzo (INAF-OAB) and P.A. Evans report on behalf of the Swift-XRT team: We have analysed 6.0 ks of XRT data for GRB 250207A, from 100 s to 73.6 ks after the BAT trigger. The data comprise 370 s in Windowed Timing (WT) mode (the first 4 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. The late-time light curve (from T0+4.2 ks) can be modelled with a power-law decay with a decay index of alpha=1.22 (+0.13, -0.10). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 2.14 (+/-0.06). The best-fitting absorption column is 6.7 (+/-1.2) x 10^20 cm^-2, in excess of the Galactic value of 2.4 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 2.02 (+0.16, -0.15) and a best-fitting absorption column of 5.5 (+3.5, -3.1) x 10^20 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.3 x 10^-11 (3.8 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 5.5 (+3.5, -3.1) x 10^20 cm^-2 Galactic foreground: 2.4 x 10^20 cm^-2 Excess significance: <1.6 sigma Photon index: 2.02 (+0.16, -0.15) If the light curve continues to decay with a power-law decay index of 1.22, the count rate at T+24 hours will be 0.010 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.4 x 10^-13 (3.9 x 10^-13) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01287821. This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/39221. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37229] LIGO/Virgo/KAGRA S250206dm: FRB 20250206A & "Time Machine" Effect.
by GCN Circulars 08 Feb '25

08 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39220 SUBJECT: LIGO/Virgo/KAGRA S250206dm: FRB 20250206A & "Time Machine" Effect. DATE: 25/02/08 00:32:54 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V. Lipunov, I. Panchenko, G. Lipunova (Lomonosow Moscow State University) In connection with the close in time (less than 1 minute) discovery of the source FRB 20250206A (GCN 39216) following the registration of the gravitational-wave signal LIGO/Virgo/KAGRA S250206dm (GCN 39175; likely either BH-NS or NS-NS) we note that this could be the first observation of the "Time Machine" effect (Lipunova, Lipunov & Panchenko, New Astronomy, Volume 2, Issue 6, 1997, 555-558;) of the FRB radio precursor phenomenon predicted earlier (Lipunov & Panchenko, 1996, A&A, 312,937L). As the authors of CHIME (GCN 39216) note, the probability of a random coincidence of the two events is quite high. However, we are confident that such an effect will inevitably be detected by means of radio and gravitational wave astronomy. We also note that the absence of a host galaxy is quite possible due to the kick velocity effect of the two supernova explosions in this binary system. View this GCN Circular online at https://gcn.nasa.gov/circulars/39220. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37228] EP-WXT trigger 01709131361: correction to GCN 39214
by GCN Circulars 08 Feb '25

08 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39219 SUBJECT: EP-WXT trigger 01709131361: correction to GCN 39214 DATE: 25/02/08 00:05:18 GMT FROM: Brendan O'Connor at Carnegie Mellon University <boconno2(a)andrew.cmu.edu> Brendan O’Connor (Carnegie Mellon U.), Malte Busmann (LMU), Daniel Gruen (LMU), Antonella Palmese (Carnegie Mellon U.), Julius Gassert (LMU), Lena Schnappinger (LMU), Julian Sommer (LMU), Lei Hu (Carnegie Mellon U.), Franziska Krause (LMU), Elia Enlghard (LMU) and Yajie Zhang (LMU) report: In Busmann et al. (GCN 39214), we reported observations of EP-WXT trigger 01709131361 with the Fraunhofer-Telescope Wendelstein (FTW). The flare star reported by Levan et al. (GCN 39218) is present in our observations, but was mistakenly rejected as an optical transient in our difference imaging due to the high proper motion and, therefore, unreliable template from the Legacy Survey. The EP trigger is very likely related to this star as initially reported by Levan et al (GCN 39218). We apologize for any confusion caused. View this GCN Circular online at https://gcn.nasa.gov/circulars/39219. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37227] EP trigger 01709131361 (possible EP250207a): NOT optical observations and flaring star
by GCN Circulars 07 Feb '25

07 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39218 SUBJECT: EP trigger 01709131361 (possible EP250207a): NOT optical observations and flaring star DATE: 25/02/07 23:22:16 GMT FROM: Andrew Levan at Radboud University <a.levan(a)astro.ru.nl> A. J. Levan (Radboud Univ and Warwick Univ.), A. van Hoof (Radboud Univ.), A. Martin-Carrillo (UCD), D.B. Malesani (DAWN/NBI and Radboud Univ.), F.E. Bauer (PUC), P.G. Jonker (Radboud Univ), G. Leloudas (DTU Space) and B. Milvang-Jensen (DAWN/NBI) report for a larger collaboration: We obtained observations of the field of the EP WXT transient (EP250207.660, trigger ID: 01709131361) with the Nordic Optical Telescope. Observations in the r-band began on 2025 Feb 7.8487 UT (4.5 hr after the EP trigger). Comparison to legacy survey observations does not reveal any plausible extragalactic counterparts to the source, consistent with earlier optical observations (Busman et al. GCN 39214), although we do note a bright galaxy at (RA=23:47:37.96, DEC=27:00:59.7) with a Legacy Survey photometric redshift of z = 0.07 +/- 0.01 (Zhou et al. 2021, MNRAS, 501, 3309) within the error box. We also note a bright flare from a high-proper motion M9 dwarf within the error box. The source is currently located at RA(J2000) = 23:47:37.44 DEC(J2000) = 27:02:06.9 It has brightened from an archival magnitude of r = 19.8+/-0.1 (Pan-STARRS) to r = 16.9+/-0.1. However, the source is identified in the Gaia DR3 catalog with a proper motion of 315.33 +/- 0.21 mas/yr. This implies it is a high proper motion, nearby star (parallax 46.76 +/- 0.16 mas) undergoing a high amplitude (+3 mag) flare. It is likely, though not conclusive, that this flare was related to the EP trigger. However, the absence of the flare in observations taken 2.5 hours earlier (Busman et al. GCN 39214) could also mean they are unrelated. We thank the observers, Fabian Mattig and Max Pritzkuleit for their excellent support in obtaining these observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/39218. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37226] GRB 250207A: Enhanced Swift-XRT position
by GCN Circulars 07 Feb '25

07 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39217 SUBJECT: GRB 250207A: Enhanced Swift-XRT position DATE: 25/02/07 22:54:13 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team. Using 1772 s of XRT Photon Counting mode data and 3 UVOT images for GRB 250207A, we find an astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 16.08929, -12.16479 which is equivalent to: RA (J2000): 01h 04m 21.43s Dec (J2000): -12d 09' 53.3" with an uncertainty of 2.2 arcsec (radius, 90% confidence). This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177). This circular was automatically generated, and is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/39217. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37225] CHIME/FRB source FRB 20250206A detected less than 1 minute after LIGO-Virgo-Kagra (LVK) S250206dm, however the probability of spatial coincidence is order 0.1%
by GCN Circulars 07 Feb '25

07 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39216 SUBJECT: CHIME/FRB source FRB 20250206A detected less than 1 minute after LIGO-Virgo-Kagra (LVK) S250206dm, however the probability of spatial coincidence is order 0.1% DATE: 25/02/07 21:26:31 GMT FROM: amanda.cook(a)mcgill.ca The CHIME/FRB Collaboration reports the spatial and temporal proximity of the LIGO-Virgo-Kagra (LVK) compact-object merger candidate S250206dm (GCN 39175; likely either BH-NS or NS-NS) and the fast radio burst (FRB) 20250206A. FRB 20250206A was detected by CHIME/FRB at 2025 Feb 06, 21:26:27.956253 p/m 0.000008 UTC (topocentric at 400 MHz) about 52 seconds (having corrected for dispersive delay) after the LVK event's topocentric time. From recorded voltage data, we obtain a best-fit localization (Michilli et al. 2021) of RA, Decl. (J2000) 338.703, 12.1699 degrees, with 1-sigma uncertainties of 0.42, 0.28 arcminutes, respectively. Using LVK code for estimating the localization region of a given position(https://bit.ly/3CJsyu6) and the most updated Bilby skymap, the FRB position is at the 99.96% credible region of the Bilby localization, i.e., the FRB position is unlikely to be spatially coincident with the LVK localization. Using our raw voltage data, the burst's structure-maximized dispersion measure (DM) is 207.117 +/- 0.003 pc cm^-3. With a Galactic disk DM estimate of 40 pc cm^-3 from NE2001 and assuming a Galactic halo DM of 38 pc cm^-3, (Yamasaki & Totani 2020), the residual extragalactic DM is ~130 pc cm^-3. Using a redshift-DM relationship for the intergalactic medium of z~ DM / 800 pc cm^-3 (Connor et al. 2024), this extragalactic DM corresponds to an upper limit on the luminosity distance (i.e., assuming no DM contribution from a host galaxy) of ~800 Mpc (assuming LambdaCDM parameters from Planck Collaboration 2018), consistent with the LVK-inferred luminosity distance of 348 +/- 114 Mpc (GCN 39184). The FRB was detected with a signal-to-noise ratio of 16.4 in one CHIME/FRB beam, and 15.7 in a second beam. A preliminary baseband fluence averaged over the entire 400-800 MHz CHIME observing band is 36 +/- 4 Jy ms (1-sigma uncertainty). The source does not appear to be a repeat burst from any previously detected CHIME FRB above a signal-to-noise ratio of 8. The source has clear scattering, with a characteristic timescale of ~0.05-0.10 ms at 600 MHz (Fonseca et al. 2023). The Galactic scattering contribution in this direction using NE2001p at 600 MHz is expected to be ~1.5µs. The burst is consistent with being 100% linearly polarized and has a Faraday rotation measure (RM) of -62.07 +/- 0.05 rad m^-2, which was determined using RM-synthesis. The Galactic RM towards the FRB is estimated to be -37 +/- 11 rad m^-2(Hutschenreuter et al. 2020). The probability of chance coincidence (i.e., the likelihood that the LVK and CHIME/FRB events are temporally and spatially proximal by chance only) is difficult to estimate immediately given the large LVK uncertainty regions and CHIME/FRB's uneven exposure and sensitivity on the sky. With the strong caveat that we do not yet know the joint probability of coincidence (analysis ongoing), and that it is likely non-negligible, we are providing the above information because any potential electromagnetic counterpart will be transient. Due to on-site networking issues, this event was not sent out to the community as a VOEvent. Below, we show the multi-beam event waterfall plot, where the panels represent adjacent beams in different rows and columns. We also show an overlay of the FRB position on top of the merger event (from GraceDB, theflat-resolution FITS file created from Bilby.fits.gz,1) Multi-beam waterfall plot: https://storage.googleapis.com/chimefrb-dev.appspot.com/FRB20250206A/multib… Localization plot: https://storage.googleapis.com/chimefrb-dev.appspot.com/FRB20250206A/chime_… View this GCN Circular online at https://gcn.nasa.gov/circulars/39216. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37224] LIGO/Virgo/KAGRA S250206dm: GOTO counterpart search update - AT2025bar
by GCN Circulars 07 Feb '25

07 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39215 SUBJECT: LIGO/Virgo/KAGRA S250206dm: GOTO counterpart search update - AT2025bar DATE: 25/02/07 20:13:57 GMT FROM: kendall.ackley(a)warwick.ac.uk D. Steeghs, K. Ackley, M.Kennedy, D. O’Neill, Y.Julakanti, S. Belkin, B. P. Gompertz, B. Godson, G. Ramsay, M. Dyer, J. Lyman, K. Ulaczyk, D. Galloway, V. Dhillon, P. O'Brien, K. Noysena, R. Kotak, R. Breton, L. Nuttall, E. Pallé, D. Pollacco, T. Killestein, and A. Kumar report on behalf of the GOTO collaboration: We report on optical observations and candidate vetting with the Gravitational-wave Optical Transient Observer (GOTO; Steeghs et al. 2022) in response to the LIGO/Virgo/KAGRA candidate NSBH event S250206dm (The LIGO-Virgo-KAGRA Collaboration, GCN 39175). Targeted observations from both GOTO-N and GOTO-S are still ongoing. Here we report on analysis of data obtained beginning at Feb. 6 2025 21:31:11 UT, (+0.09h post trigger) and continuing through to Feb. 7 2025 18:07:58 UT (+20.71h post trigger). These cover 347 sqr. deg. within the 90% localisation contour, equivalent to 35.6% of the total 2D localisation probability. Images were processed immediately after acquisition using the GOTO pipeline with an average 5-sigma depth of 20.1 mag (L band 400-700 nm). Difference imaging was performed using deeper template observations. Source candidates were initially filtered using a classifier (Killestein et al. 2021) and cross-matched against a variety of contextual and minor planet catalogs. Human vetting was carried out in real time on any candidates that passed the above checks. We report the detection of a variable transient, GOTO25aeb / AT2025bar (https://www.wis-tns.org/object/2025bar). Although individual detections are not very significant, the transient is detected multiple times and appears to be fading over the course of our observations (spanning 4 hours). It is likely associated with a host galaxy listed in the WISExSuperCOSMOS PhotoZ SVM catalogue as WISExSCOS J112243.56-453426.1 at a (photo) redshift of z ~ 0.17 (D_L = 840 Mpc). Although not necessarily matching the expectations for an EM counterpart, we believe further investigation of this transient is warranted. +--------------------------------------------------------------------------+ | Internal name | IAU name | RA(J2000) | Dec(J2000) | Mag(AB) | +--------------------------------------------------------------------------+ | GOTO25aeb | AT2025bar | 11:22:43.66, -45:34:28.58 | 20.32 +/- 0.15 | +--------------------------------------------------------------------------+ Magnitudes were calibrated using ATLAS-REFCAT2 (Tonry et al. 2018) and not corrected for Galactic extinction. GOTO (https://goto-observatory.org) is a network of telescopes that is principally funded by the STFC and operated at the Roque de los Muchachos Observatory on La Palma, Spain, and Siding Spring Observatory in NSW, Australia, on behalf of a consortium including the University of Warwick, Monash University, Armagh Observatory & Planetarium, the University of Leicester, the University of Sheffield, the National Astronomical Research Institute of Thailand (NARIT), the University of Turku, the University of Portsmouth, the University of Manchester and the Instituto de Astrofisica de Canarias (IAC). View this GCN Circular online at https://gcn.nasa.gov/circulars/39215. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37223] EP-WXT trigger 01709131361 / LIGO/Virgo/KAGRA S250206dm: FTW optical and NIR observations
by GCN Circulars 07 Feb '25

07 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39214 SUBJECT: EP-WXT trigger 01709131361 / LIGO/Virgo/KAGRA S250206dm: FTW optical and NIR observations DATE: 25/02/07 19:58:43 GMT FROM: Malte Busmann at Ludwig-Maximilians-Universität München <m.busmann(a)physik.lmu.de> Malte Busmann (LMU), Daniel Gruen (LMU), Brendan O’Connor (Carnegie Mellon U.) and Antonella Palmese (Carnegie Mellon U.), Julius Gassert (LMU), Lena Schnappinger (LMU), Julian Sommer (LMU), Lei Hu (Carnegie Mellon U.), Franziska Krause (LMU), Elia Enlghard (LMU) and Yajie Zhang (LMU) report: We observed the 90% localization of EP-WXT trigger 01709131361, which lies inside of the 70% localization of S250206dm (LIGO Scientific Collaboration, GCN 39184) with the Three Channel Imager (3KK) at the Fraunhofer-Telescope Wendelstein (FTW) in the r, i and J band simultaneously for 17 x 180 s under suboptimal sky conditions. The observations started at 2025-02-07T17:52:05 UT (2.0 h after the EP-WXT trigger and 20.4 h after the NSBH/BNS merger). We performed difference imaging in the r band with templates from the DESI Legacy Surveys and do not identify any variable optical sources to a 3-sigma depth of r>20.9 AB mag calibrated to the PS1 catalog. Further observations are encouraged. We thank Christoph Ries from the Wendelstein Observatory for obtaining these observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/39214. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37222] GRB 250129A: ABObservatory SLOAN r’ afterglow detection
by GCN Circulars 07 Feb '25

07 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39213 SUBJECT: GRB 250129A: ABObservatory SLOAN r’ afterglow detection DATE: 25/02/07 18:49:05 GMT FROM: A. Brosio at ABObservatory Rosarno <antonino.brosio(a)gmail.com> A. Brosio (ABObservatory), S. Savaglio (University of Calabria), S. Tosi, S. Zappatore & P. Cianfarra (University of Genoa), S. Benatti (INAF Palermo), M. Rainer (INAF Brera), D. Ricci (INAF Padova), A. Di Dato (INAF Capodimonte), S. Masiero & A. Nastasi (GAL Hassin), L. Betti (Osservatorio Polifunzionale del Chianti), D. Liguori (Osservatorio “G. Galilei” Cariati) for the NOCTIS team report: We observed the field of GRB 250129A, which was detected by Swift (Beardmore et al., GCN 39066) with the 30-cm automated telescope at ABObservatory (Rosarno, Italy) using the SLOAN r’ filter. Observations began on 2025 January 30 at 23:41:31 UT, approximately 43 hours after the Swift trigger. The observation consisted of 10 exposures of 240 seconds each, with variable conditions due to passing clouds during the session. The mid-exposure time was 00:07:31 UT, and the final exposure ended at 00:33:31 UT. From photometry, we detect the optical counterpart in our images at the position of the previously reported afterglow (Francile et al., GCN 39065; Schneider et al., GCN 39071; Belkin et al., GCN 39072; Izzo et al., GCN 39073; Izzo & Malesani, GCN 39074; Gosh et al., GCN 39077; Schneider et al., GCN 39078). The measured magnitude is: r’ = 19.32 +/- 0.13 (AB, calibrated against the Pan-STARRS catalogue on SIMBAD) at a mid-time of t - t0 = 00:12:43 after the trigger. View this GCN Circular online at https://gcn.nasa.gov/circulars/39213. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37221] GRB 250207A: REM IR afterglow detection
by GCN Circulars 07 Feb '25

07 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39212 SUBJECT: GRB 250207A: REM IR afterglow detection DATE: 25/02/07 18:01:45 GMT FROM: Matteo Ferro at INAF-OAB <matteo.ferro(a)inaf.it> M. Ferro, R. Brivio, P. D’Avanzo, S. Covino, D. Fugazza (INAF-OAB) report on behalf of the REM team: We observed the field of GRB 250207A, detected by Fermi/GBM (Fermi GBM Team, GCN 39181) and Swift/BAT (Ferro et al., GCN 39182) with the REM 60cm robotic telescope located at the ESO observatory of La Silla (Chile). The observations were carried in the g, r, i, z, J, H, K bands, starting on 2025 February 07 at 01:17:08 UT (i.e. 61 s after the Swift trigger), and lasting for about 2 hours. From preliminary photometry we detect the counterpart in the IR images at the position of the optical afterglow (Angulo et al., GCN 39186; Kuin & Ferro, GCN 39199; Brivio et al., GCN 39202; Jelinek et al., GCN 39209) with the following magnitude: H ~ 13.3 (Vega; calibrated against the 2MASS catalogue) at a mid-time of t - t0 = 26.6 minutes after the trigger. View this GCN Circular online at https://gcn.nasa.gov/circulars/39212. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37220] LIGO/Virgo/KAGRA S250206dm: ATLAS observations of the skymap
by GCN Circulars 07 Feb '25

07 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39211 SUBJECT: LIGO/Virgo/KAGRA S250206dm: ATLAS observations of the skymap DATE: 25/02/07 17:53:35 GMT FROM: S. Srivastav at Oxford <shubhamsrivastav(a)gmail.com> K. W. Smith(QUB/Oxford), C. R. Angus, D. R. Young (QUB), S. J. Smartt (QUB/Oxford), S. Srivastav, J. Gillanders (Oxford), M. Nicholl, M. D. Fulton, T. Moore, A. Aamer, M. McCollum, S. Sim, J. Weston, X. Sheng, D. Magill, P. Ramsden (QUB), L. Shingles (GSI/QUB, H. Stevance, F. Stoppa, A. Cooper (Oxford), L. Rhodes (TSI/McGill),L. Denneau, J. Tonry, H. Weiland, R. Siverd (IfA, University of Hawaii), N. Erasmus, W. Koorts (South African Astronomical Observatory), A. Rest (STScI), T.-W. Chen (NCU), C. Stubbs (Harvard), J. Sommer (LMU), B. Schmidt (ANU) We report observations of the Bilby.fits skymap of the NSBH merger event S250206dm (The LIGO-Virgo-Kagra Collaboration, GCN 39175) by the ATLAS survey (Tonry et al., 2018, PASP, 13, 164505). ATLAS is a quadruple 0.5m optical telescope survey system (Hawaii, South Africa, Chile) employing two filters, cyan and orange. In our primary NASA mission for Near-Earth Object discovery, we cover the entire visible night sky every 24 hrs to magnitude depths m ~ 19.5, weather and Moon permitting. We targeted the accessible skymap of S250206dm with a sequence of quads (4 x 110 s images) obtained at each pointing position. Data acquisition began at MJD 60713.098 or 2024-04-22 02:21:07 (UTC), 0.8 hrs after the LVC initial alert and 5.0 hrs after the merger event (which was 60712.89). The images were processed with the ATLAS pipeline, and reference images were subtracted. Transient candidates were identified and run through our standard filtering procedures (Smith et al., 2020, PASP, 132, 1). We covered 389 square degrees of the bilby.fits skymap 90% area, and covered a sky region totalling 35% of the event's full localisation likelihood. Observations lasted between ~5 hrs to 10.5 hrs after the NSBH/BNS merger. We found no plausible new transient sources that had not been previously detected by ATLAS before the merger event or reported to the IAU Transient name server. The 5-sigma depths of our images were typically o < 19.5 +/- 0.6 AB mag. We are reporting all discoveries to the TNS, where they can be tracked, classified, searched, and commented upon. The Asteroid Terrestrial-impact Last Alert System (ATLAS) project is primarily funded to search for Near-Earth asteroids through NASA grants NN12AR55G, 80NSSC18K0284, and 80NSSC18K1575; byproducts of the NEO search include images and catalogs from the survey area. This work was partially funded by Kepler/K2 grant J1944/80NSSC19K0112 and HST GO-15889, and STFC grants ST/T000198/1 and ST/S006109/1. The ATLAS science products have been made possible through the contributions of the University of Hawaii Institute for Astronomy, University of Oxford, the Queen's University Belfast, the Space Telescope Science Institute, the South African Astronomical Observatory, and The Millennium Institute of Astrophysics (MAS), Chile. View this GCN Circular online at https://gcn.nasa.gov/circulars/39211. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37219] LIGO/Virgo/KAGRA S250206dm: Pan-STARRS survey of the skymap for optical transients
by GCN Circulars 07 Feb '25

07 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39210 SUBJECT: LIGO/Virgo/KAGRA S250206dm: Pan-STARRS survey of the skymap for optical transients DATE: 25/02/07 17:49:06 GMT FROM: S. Srivastav at Oxford <shubhamsrivastav(a)gmail.com> D. R. Young (QUB), J. H. Gillanders (Oxford), M. E. Huber, K. C. Chambers (IfA, Hawaii), S. J. Smartt, K. W. Smith (Oxford/QUB), S. Srivastav, F. Stoppa (Oxford), C. R. Angus, M. Nicholl, M. D. Fulton, M. McCollum, T. Moore, S. Sim, J. Weston, A. Aamer, X. Sheng (QUB), P. Ramsden (QUB/Birmingham), L. Shingles (GSI/QUB), H. Stevance,(Oxford), L. Rhodes (TSI/McGill), A. S. B. Schultz, T. de Boer, J. Fairlamb, H. Gao, C. C. Lin, T. Lowe, E. Magnier, P. Minguez, G. Paek, A. Smith, R. J. Wainscoat (IfA, Univ. Hawaii), T.-W. Chen (NCU), A. Rest (STScI), C. Stubbs (Harvard): We report observations of the Bilby.fits skymap of the NSBH merger event S250206dm (The LIGO-Virgo-Kagra Collaboration, GCN 39175) with the Pan-STARRS telescope system (Chambers et al., 2016, ArXiv e-prints, 1612.05560). The Pan-STARRS system comprises of two 1.8m telescope units located at the summit of Haleakala on the Hawaiian island of Maui, employing an SDSS-like filter system denoted as grizy, and a broad w-filter, which is a composite of the gri-filters. Tiling sequences of multiple 45-sec images were taken at each pointing position in the r-band with both Pan-STARRS1 and Pan-STARRS2. The images were processed with the Pan-STARRS pipeline. After astrometric and photometric calibration, reference images were subtracted from the target stacked images (Magnier et al., 2020a, ApJS, 251, 3; Magnier et al., 2020b, ApJS, 251, 6; Waters et al., 2020, ApJS, 251, 4). Transient candidates were identified and run through our standard filtering procedures, including rejection of artifacts with machine learning tools and cross-matching with galaxy, stellar and solar-system catalogs (e.g. Smith et al., 2020, PASP, 132, 1; Smartt et al. 2024, MNRAS 528, 2299). We covered 298 square degrees of the bilby.fits skymap 90% area, and covered a sky region totalling 32% of the event's full localisation. Data acquisition began at MJD 60713.23 or 2025-02-07 05:31:12 (UTC), 8.16 hrs after the merger event (which was on MJD 60712.89). The last image was taken at 60713.45. We found a number of plausible new extragalactic transient candidates which we have reported to the TNS. These were mostly found coincident with compact galaxies or ambiguous star/galaxy sources. We have no reason to favour any of them being a transient in a galaxy within the Bilby.fits distance of 348 +/- 114 Mpc and being a good candidate for the counterpart to S250206dm. Thus we do not highlight them here, but they can be found and matched on the TNS. The depths of these 45 sec images were typically (3.5 sigma) r < 20.0 +/- 0.4. Any transients we do find during further processing will be reported to the TNS, where they can be tracked, classified, searched, and commented upon. We encourage further information to be reported on the TNS object pages. We will re-process the 45 second exposures into deeper stacks and re-run them through the detection pipeline. Operation of the Pan-STARRS1 and Pan-STARRS2 telescopes is primarily supported by the National Aeronautics and Space Administration under Grant No. NNX12AR65G and NNX14AM74G, issued through the SSO Near-Earth Object Observations Program. Data processing is enabled by Queen's University Belfast and the University of Oxford, enabled through STFC grants ST/Y001605/1, ST/T000198/1 and ST/X001253/1, the Royal Society, and the Hintze Centre for Astrophysical Surveys. View this GCN Circular online at https://gcn.nasa.gov/circulars/39210. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37218] GRB 250207A: FRAM-Auger optical detection
by GCN Circulars 07 Feb '25

07 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39209 SUBJECT: GRB 250207A: FRAM-Auger optical detection DATE: 25/02/07 17:00:05 GMT FROM: Martin Jelinek at Astro.Inst-AVCR,Ondrejov <martin.jelinek(a)asu.cas.cz> Martin Jelinek (ASU CAS Ondrejov, CZ), Martin Masek, Petr Janecek, Sergey Karpov, Jakub Jurysek, Jan Ebr, Ronan Cunniffe, Petr Travnicek, Michael Prouza (Institute of Physics, Prague, CZ) and Jan Strobl (ASU CAS Ondrejov, CZ) report: The 30cm robotic telescope FRAM-Auger in Malargue (Argentina) reacted robotically to the Swift/BAT and Fermi/GBM alert of GRB250207A (Fermi GBM Team, GCN 39181; Ferro et al., GCN 39182), starting with a series of 20s R-band images at 01:16:49 UT, i.e. 42s post trigger. We detect the optical afterglow at the position reported by Brivio et al. (GCN 39202), Kuin & Ferro (GCN 39199), and Angulo et al. (GCN 39186) in our initial frames. The early light curve shows a relatively steep decay with a power-law index alpha ~ 1.6. Extrapolation of this decay rate appears inconsistent with later observations by COLIBRI (Angulo et al., GCN 39186), suggesting a possible transition in the light curve slope beyond ~600s post burst. View this GCN Circular online at https://gcn.nasa.gov/circulars/39209. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37217] LIGO/Virgo/KAGRA S250206dm: DDOTI Upper Limits
by GCN Circulars 07 Feb '25

07 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39208 SUBJECT: LIGO/Virgo/KAGRA S250206dm: DDOTI Upper Limits DATE: 25/02/07 16:57:22 GMT FROM: Rosa L. Becerra at Tor Vergata, Roma <rosa.becerra(a)roma2.infn.it> LIGO/Virgo/KAGRA S250206dm: DDOTI Upper Limits Rosa L. Becerra (U Rome), Simone Dichiara (Penn State University), Alan M. Watson (UNAM), William H. Lee (UNAM), Camila Angulo Valdez (UNAM), Eleonora Troja (U Rome), Nat Butler (ASU), Tsvetelina Dimitrova (ASU), Alexander Kutyrev (GSFC/UMD), Océlotl López (UNAM), and Margarita Pereyra (UNAM) report: We observed LIGO/Virgo/KAGRA S250206dm candidate (LVKC, GCN 39175) with the DDOTI/OAN wide-field imager at the Observatorio Astronómico Nacional on Sierra San Pedro Mártir (http://ddoti.astroscu.unam.mx) on the night of 2025-02-07 UTC. We tiled the LVK localization with 5 pointings covering about 127 square degrees and including about 14% of the probability in the most recent Bilby map. We observed from 2025-02-07 02:18 UTC to 2025-02-07 12:22 UTC (from T+4.9 to T+15.0 hours after the event) obtaining a total of 2.65 hours of exposure across the fields in the w filter, with 10-sigma limiting AB magnitudes between w~18-19.5. Comparing our observations to the USNO-B1 and PanSTARRS PS1 DR2 catalogs, we identified the increase of brightness in two sources within the 95% probability region at positions: Source 1: RA, Dec= 09:59:01.76 -16:33:22.6 with w=19.1+/-0.1 Source 2: RA, Dec= 09:59:24.44 -16:29:37.4 with w=19.3+/-0.1 These positions are related to previous catalogued sources in the Legacy Survey DR10 (Dey et al. 2019). Source 1 has a reported magnitude r=21.8 (with a photo-z=0.45) whereas source 2 of r=22 (with a photo-z=0.66). Further observations are planned. We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir. View this GCN Circular online at https://gcn.nasa.gov/circulars/39208. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37216] GRB 250207B: Tiled Swift observations
by GCN Circulars 07 Feb '25

07 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39207 SUBJECT: GRB 250207B: Tiled Swift observations DATE: 25/02/07 16:37:22 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> P. A. Evans (U. Leicester) reports on behalf of the Swift team: Swift has initiated a series of observations, tiled on the sky, of the MAXI GRB 250207B. Automated analysis of the XRT data will be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00131 Any uncatalogued X-ray sources detected in this analysis will be reported on this website and via GCN COUNTERPART notices. The probability of finding serendipitous sources, unrelated to the MAXI event is high: any X-ray source considered to be a probable afterglow candidate will be reported via a GCN Circular after manual consideration. Details of the XRT automated analysis methods are detailed in Evans et al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8). This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/39207. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37215] LIGO/Virgo/KAGRA S250207bg: NED Galaxies in the Localization Volume
by GCN Circulars 07 Feb '25

07 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39206 SUBJECT: LIGO/Virgo/KAGRA S250207bg: NED Galaxies in the Localization Volume DATE: 25/02/07 16:10:21 GMT FROM: David Cook at Caltech/IPAC-NED <dcook(a)ipac.caltech.edu> David O. Cook (Caltech/IPAC), Rick Ebert (Caltech/IPAC), George Helou (Caltech/IPAC), Joseph M. Mazzarella (Caltech/IPAC), Marion Schmitz (Caltech/IPAC), and Leo Singer (NASA/GSFC) On behalf of the NASA/IPAC Extragalactic Database (NED) Team. We spatially cross-matched the LVK S250207bg-3-Initial sky localization with the NED Local Volume Sample (NED-LVS; Cook et al. 2023), which is a subset of NED with a redshift or redshift-independent distance less than 1000 Mpc. We find 7591 galaxies within the 90% containment volume, and we list here the top 20 galaxies sorted by the joint probability of the 3D localization and the WISE W1 luminosity (an observable proxy for stellar mass). For the full or top 20 list of galaxies in the 90% volume go either to the NED Gravitational Wave Followup service at https://ned.ipac.caltech.edu/uri/NED::GWF/ or click on the following links: Full List Download: https://ned.ipac.caltech.edu/uri/NED::GWFglist/fits/S250207bg/3 Top 20 List Download: https://ned.ipac.caltech.edu/uri/NED::GWFglist/fits/S250207bg/3/20 The NED-GWF service provides downloadable galaxy lists and visualizations for candidate host galaxies. For each GW alert, these products are automatically generated and made available within minutes to expedite efficient electromagnetic follow-up observations. The NED top 20 list is sorted by the joint probability of the 3D localization and the WISE W1 luminosity, but users can sort on additional pre-computed prioritization metrics (star formation rate, P_3D * P_SFR; and specific star formation rate, P_3D * P_sSFR; etc.) which are available via downloading the entire galaxy list inside the event's probability volume. | objname| ra| dec|objtype| DistMpc|DistMpc_unc| m_NUV| m_NUV_unc| m_Ks| m_Ks_unc| m_W1| m_W1_unc| P_3D|P_3D_LumW1| |-------------------------|--------------|--------------|-------|-----------|-----------|------------|------------|------------|------------|------------|------------|--------|----------| |WISEA J153919.63+190427.7| 234.83187| 19.07453| G| 530.26| null| null| null| 13.627| 0.172| 10.078| 0.006|5.48e-07| 2.24e-09| |WISEA J152319.42+240611.6| 230.83105| 24.10320| G| 663.87| 0.16| null| null| 14.431| 0.157| 10.454| 0.006|3.80e-07| 1.72e-09| |WISEA J154012.34+184306.0| 235.05140| 18.71817| G| 417.30| 0.08| null| null| 13.309| 0.160| 9.114| 0.005|2.45e-07| 1.51e-09| |WISEA J153645.35+185715.6| 234.18906| 18.95426| G| 614.30| 0.14| null| null| 14.462| 0.165| 11.145| 0.006|6.31e-07| 1.29e-09| |WISEA J150631.38+283419.0| 226.63079| 28.57192| G| 515.26| 0.04| null| null| 13.286| 0.172| 10.718| 0.006|5.69e-07| 1.21e-09| |WISEA J155025.85+130154.2| 237.60767| 13.03173| G| 581.25| 0.10| null| null| 13.459| 0.155| 10.806| 0.006|4.18e-07| 1.05e-09| |WISEA J151550.70+275958.5| 228.96137| 27.99951| G| 504.04| 0.05| 20.968| 0.139| 13.749| 0.153| 10.538| 0.006|3.27e-07| 7.89e-10| | [HB89] 1552+085| 238.68574| 8.37263| QSO| 557.07| 0.06| 17.225| 0.024| 12.724| 0.045| 11.383| 0.023|5.56e-07| 7.54e-10| |WISEA J151458.01+273639.7| 228.74172| 27.61105| G| 560.27| 0.21| 22.052| 0.306| 11.568| 0.117| 11.617| 0.007|6.48e-07| 7.15e-10| |WISEA J155856.52+032444.3| 239.73542| 3.41238| G| 408.76| 0.10| null| null| 12.955| 0.169| 10.037| 0.006|2.71e-07| 6.96e-10| |WISEA J153250.52+200718.3| 233.21046| 20.12169| G| 681.89| 0.13| null| null| 13.831| 0.187| 10.888| 0.006|1.99e-07| 6.42e-10| | 3C 327| 240.61406| 1.96560| G| 486.72| 2.15| 20.654| 0.174| 12.897| 0.047| 11.037| 0.006|4.26e-07| 6.11e-10| |WISEA J155639.59+111348.0| 239.16499| 11.22994| G| 486.41| 0.14| null| null| 14.133| 0.119| 9.442| 0.006|9.76e-08| 6.04e-10| |WISEA J154320.19+143045.0| 235.83416| 14.51254| G| 622.09| 0.04| null| null| 13.890| 0.198| 11.215| 0.006|2.64e-07| 5.21e-10| |WISEA J151556.87+264556.0| 228.98694| 26.76548| G| 592.88| null| null| null| 13.560| 0.139| 12.348| 0.011|8.01e-07| 5.06e-10| |WISEA J145244.45+315248.3| 223.18524| 31.88009| G| 537.68| 0.07| null| null| 12.904| 0.040| 11.775| 0.006|5.42e-07| 4.75e-10| |WISEA J150746.48+284911.8| 226.94359| 28.81997| G| 515.60| 0.75| 20.018| 0.182| 12.395| 0.100| 12.063| 0.007|7.53e-07| 4.66e-10| |WISEA J145519.43+321511.0| 223.83099| 32.25305| G| 538.51| 0.21| null| null| 13.017| 0.046| 11.996| 0.008|5.89e-07| 4.23e-10| |WISEA J145331.46+302133.9| 223.38103| 30.35929| G| 566.40| 0.12| 22.065| 0.341| 14.897| 0.264| 9.870| 0.006|7.14e-08| 4.02e-10| |WISEA J154015.93+175229.2| 235.06642| 17.87478| G| 474.23| null| null| null| 12.689| 0.157| 11.861| 0.007|6.29e-07| 3.97e-10| Table 1: Top 20 galaxies in NED-LVS that fall in the 90% probability volume for S250207bg sorted by the joint probability of 3D position and WISE W1 luminosity (P_3D * P_LumW1). Galaxy is the NED preferred name. RA and Dec are the Equatorial coordinates in degrees (J2000). Objtype is the object type of the galaxy candidate. Distance is the distance to the galaxy in Mpc. m_NUV and mErr_NUV are the apparent magnitude and error from GALEX. m_Ks and mErr_Ks are the apparent magnitude and error from 2MASS. m_W1 and mErr_W1 are the apparent magnitude and error from AllWISE. P_3D is the probability that the galaxy is in the volume given the distance of GW event. P_3D_LumW1 is the joint probability within the volume weighted by the WISE1 luminosity of the galaxy (P_3D * P_LumW1). View this GCN Circular online at https://gcn.nasa.gov/circulars/39206. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37214] Konus-Wind detection of GRB 250204B
by GCN Circulars 07 Feb '25

07 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39205 SUBJECT: Konus-Wind detection of GRB 250204B DATE: 25/02/07 15:46:33 GMT FROM: Anna Ridnaia at Ioffe Institute <ridnaia(a)mail.ioffe.ru> A. Ridnaia, D. Frederiks, A. Lysenko, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report: The short-duration GRB 250204B (Fermi-GBM detection: Fermi GBM team, GCN 39141; AstroSat CZTI detection: Dasgupta et al., GCN 39142; IPN triangulation: Svinkin et al., GCN 39145; SVOM/GRM observation: Zhang et al., GCN 39163) triggered Konus-Wind at T0=24073.659 s UT (06:41:13.659). The burst light curve shows a single pulse which starts at ~T0-0.1 s and has a total duration of ~1.5 s. The emission is seen up to ~2 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB250204_T24073/ As observed by Konus-Wind, the burst had a fluence of 2.99(-0.29,+0.37)x10^-6 erg/cm2, and a 16-ms peak flux, measured from T0+0.008 s, of 7.51(-1.64,+1.74)x10^-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-averaged spectrum of the burst (measured from T0 to T0+0.256 s) is best fit in the 20 keV - 10 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.85(-0.17,+0.19) and Ep = 383(-66,+92) keV (chi2 = 16/22 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2.1 (chi2 = 16/21 dof). All the quoted errors are at the 68% confidence level. All the quoted values are preliminary. View this GCN Circular online at https://gcn.nasa.gov/circulars/39205. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37213] IGO/Virgo/KAGRA S250206dm: Virtual Telescope Project upper limit for the Neutrino IceCube Candidate
by GCN Circulars 07 Feb '25

07 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39204 SUBJECT: IGO/Virgo/KAGRA S250206dm: Virtual Telescope Project upper limit for the Neutrino IceCube Candidate DATE: 25/02/07 14:01:44 GMT FROM: Gianluca Masi at Virtual Telescope Project <gianluca(a)bellatrixobservatory.org> Gianluca Masi (Virtual Telescope Project) reports: Following up LIGO/Virgo/KAGRA S250206dm (LVKC, GCN 39175) at optical wavelengths, we managed to image the field centered at position RA = 149.16, Decl. =-17.94 and covering the complete 0.43 deg. error region reported by the IceCube Collaboration (GCN 39176), remotely using our 250mm-f/4.5 robotic astrograph installed at our facility in Manciano (GR), Italy. We collected 35 x 120s unfiltered exposures under significant moonlight, with a total integration of 70 minutes, centered on 22:53:35 UTC, 06 Feb. 2025, about 1.5 hours after the event. A CMOS camera based on the Sony IMX455 sensor was used. Comparing the resulting image with the POSS2, blue filter, we did not record any obvious new source, down to mag. 19. View this GCN Circular online at https://gcn.nasa.gov/circulars/39204. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37212] IceCube-250207A - IceCube observation of a high-energy neutrino candidate track-like event
by GCN Circulars 07 Feb '25

07 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39203 SUBJECT: IceCube-250207A - IceCube observation of a high-energy neutrino candidate track-like event DATE: 25/02/07 13:48:55 GMT FROM: Giacomo Sommani at Ruhr-Universität Bochum <gsommani(a)icecube.wisc.edu> The IceCube Collaboration (http://icecube.wisc.edu/) reports: On 2025-02-07 at 02:07:55.27 UT IceCube detected a track-like event with a high probability of being of astrophysical origin. The event was selected by the ICECUBE_Astrotrack_BRONZE alert stream. The average astrophysical neutrino purity for bronze alerts is 30%. This alert has an estimated false alarm rate of 1.45 events per year due to atmospheric backgrounds. The IceCube detector was in a normal operating state at the time of detection. After the initial automated alert (https://gcn.gsfc.nasa.gov/notices_amon_g_b/140472_78196104.amon), more sophisticated reconstruction algorithms have been applied offline, with the direction refined to: Date: 2025-02-07 Time: 02:07:55.27 UT RA: 132.93 (+2.05, -1.89 deg 90% PSF containment) J2000 Dec: 20.66 (+1.28, -1.40 deg 90% PSF containment) J2000 Two Fermi 4FGL or 3FHL catalog sources are in the 90% uncertainty region: 4FGL J0854.8+2006 and 4FGL J0856.8+2056, located 0.9 deg and 1.2 deg away from the best-fit position, respectively. We encourage further follow-up by ground and space-based instruments to help identify a possible astrophysical source for the candidate neutrino. The IceCube Neutrino Observatory is a cubic-kilometer neutrino detector operating at the geographic South Pole, Antarctica. The IceCube realtime alert point of contact can be reached at roc(a)icecube.wisc.edu View this GCN Circular online at https://gcn.nasa.gov/circulars/39203. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37211] GRB 250207A: REM optical afterglow detection
by GCN Circulars 07 Feb '25

07 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39202 SUBJECT: GRB 250207A: REM optical afterglow detection DATE: 25/02/07 13:23:26 GMT FROM: Riccardo Brivio at INAF-OAB <riccardo.brivio(a)inaf.it> R. Brivio, M. Ferro, P. D’Avanzo, S. Covino (INAF-OAB), A. Melandri (INAF-OAR), D. B. Malesani (DAWN/NBI and Radboud Univ.), G. Tagliaferri, D. Fugazza (INAF-OAB) report on behalf of the REM team: We observed the field of GRB 250207A, detected by Fermi/GBM (Fermi GBM Team, GCN 39181) and Swift/BAT (Ferro et al., GCN 39182) with the REM 60cm robotic telescope located at the ESO observatory of La Silla (Chile). The observations were carried in the g, r, i, z, J, H, K bands, starting on 2025 February 07 at 01:17:08 UT (i.e. 61 s after the Swift trigger), and lasting for about 2 hours. From preliminary photometry we detect the counterpart in the optical images at the position of the optical afterglow (Angulo et al., GCN 39186; Kuin & Ferro, GCN 39199) with the following magnitude: r = 12.7 +/- 0.1 (AB; calibrated against the Pan-STARRS catalogue) at a mid-time of t - t0 = 66 s after the trigger. The analysis of the NIR data is ongoing. View this GCN Circular online at https://gcn.nasa.gov/circulars/39202. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37210] LIGO/Virgo/KAGRA S250207bg: Identification of a GW compact binary merger candidate
by GCN Circulars 07 Feb '25

07 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39201 SUBJECT: LIGO/Virgo/KAGRA S250207bg: Identification of a GW compact binary merger candidate DATE: 25/02/07 12:27:19 GMT FROM: Luise Kranzhoff at Maastricht University <luise.kranzhoff(a)ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S250207bg during real-time processing of data from LIGO Livingston Observatory (L1) and Virgo Observatory (V1) at 2025-02-07 11:56:45.258 UTC (GPS time: 1422964623.258). The candidate was found by the GstLAL [1] and SPIIR [2] analysis pipelines. S250207bg is an event of interest because its false alarm rate, as estimated by the online analysis, is 4.9e-36 Hz, or about one in 1e28 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S250207bg After parameter estimation by RapidPE-RIFT [3], the classification of the GW signal, in order of descending probability, is BBH (>99%), NSBH (<1%), BNS (<1%), or Terrestrial (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [4] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [4] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 29 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 110 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 546 +/- 98 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [2] Chu et al. PRD 105, 024023 (2022) doi:10.1103/PhysRevD.105.024023 [3] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002 [4] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [5] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013 View this GCN Circular online at https://gcn.nasa.gov/circulars/39201. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37209] LIGO/Virgo/KAGRA S250206dm:GLADEnet Completeness: Potential Host Galaxies in the 90% Credible Volume
by GCN Circulars 07 Feb '25

07 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39200 SUBJECT: LIGO/Virgo/KAGRA S250206dm:GLADEnet Completeness: Potential Host Galaxies in the 90% Credible Volume DATE: 25/02/07 11:45:22 GMT FROM: Maria Lisa Brozzetti at Università degli Studi di Perugia <marialisa.brozzetti(a)ligo.org> M. L. Brozzetti (UniPG/INFN), G. Dálya (L2IT/EotvosU), G. Greco (INFN), M. Bawaj (UniPG/INFN), T. Matcovich (UniPG/INFN), S. Cutini (INFN) , R. De Pietri (UniPR/INFN), Marica Branchesi (GSSI), Elahe Khalouei(IPM) On behalf of the GLADEnet Team. We analyzed the completeness of the GLADE+ [1] catalog within the 90% credible localization volume of the S250206dm event from the Update-6 alert from the GCN Circular 39175. The completeness value is 5.6e-1 in the B-band using the last released skymap : Bilby.multiorder.fits,1 , which means that the catalogue contains 56% of the total light in the B-band expected from galaxies in the localization volume. A total of 107,012 galaxies are identified within the 90% gravitational volume. The complete list of galaxies can be downloaded from the GLADEnet webpage [2] : https://virgo.pg.infn.it/gladenet/catalogs/ GLADEnet allows for the interactive visualization of the 90% localization area and its intersection with regions of high extinction as defined in GLADE+. Furthermore, the first 1000 galaxies can be explored interactively, enabling users to filter galaxies based on their 3D probability density or their absolute B magnitude. The ligo.skymap cross-match method [3,4] is used to obtain the list of galaxies. References: [1]GLADE+: An Extended Galaxy Catalogue for Multimessenger Searches with Advanced Gravitational-wave Detectors G. Dálya et al. MNRAS, 514,1, pp.1403-1411, 2022 [2] GLADEnet: A progressive web app for multi-messenger cosmology and electromagnetic follow-ups of gravitational-wave sources M. L. Brozzetti, G. Dálya, G. Greco, M. Bawaj, T. Matcovich, M. Branchesi, T. Boch, M. Baumann, S. Cutini, R. De Pietri et al. (4 more) A&A, 684, A44 (2024) [3] Singer, L. P., Chen, H.-Y., Holz, D. E., et al. 2016, Astropys. J. Lett., 829, L15. doi:10.3847/2041-8205/829/1/L15 [4] Singer, L. P., Chen, H.-Y., Holz, D. E., et al. 2016, Astropys. J. Supp., 226, 10. doi:10.3847/0067-0049/226/1/10 View this GCN Circular online at https://gcn.nasa.gov/circulars/39200. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37208] GRB 250207A: Swift/UVOT Detection
by GCN Circulars 07 Feb '25

07 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39199 SUBJECT: GRB 250207A: Swift/UVOT Detection DATE: 25/02/07 10:42:24 GMT FROM: Paul Kuin at MSSL <npkuin(a)gmail.com> Paul Kuin (MSSL/UCL) and M. Ferro (INAF-OAB) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 250207A 113 s after the BAT trigger (Ferro et al., GCN Circ. 39182). The source was also reported by Angulo et al. GCN Circ. 39186. The preliminary UVOT position is: RA (J2000) = 01:04:21.39 = 16.08912 (deg.) Dec (J2000) = -12:09:52.5 = -12.16459 (deg.) with an estimated uncertainty of 0.42 arc sec. (radius, 90% confidence). Preliminary detections using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white 113 263 147 15.00 +/- 0.02 v 655 674 19 16.89 +/- 0.20 b 581 600 19 16.56 +/- 0.09 u 326 575 246 15.65 +/- 0.03 uvm2 679 699 19 > 17.3 (3 sigma UL) uvw2 630 650 19 > 17.6 (3 sigma UL) The lack of detection in the UVM2 band may indicate a redshift greater than 1.3. The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.027 in the direction of the burst (Schlegel et al. 1998). View this GCN Circular online at https://gcn.nasa.gov/circulars/39199. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37207] LIGO/Virgo/KAGRA S250206dm: DDOTI Upper Limit for the Neutrino IceCube Candidate
by GCN Circulars 07 Feb '25

07 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39198 SUBJECT: LIGO/Virgo/KAGRA S250206dm: DDOTI Upper Limit for the Neutrino IceCube Candidate DATE: 25/02/07 10:37:39 GMT FROM: Rosa L. Becerra at Tor Vergata, Roma <rosa.becerra(a)roma2.infn.it> Rosa L. Becerra (U Rome), Alan M. Watson (UNAM), William H. Lee (UNAM), Camila Angulo Valdez (UNAM), Eleonora Troja (U Rome), Nat Butler (ASU), Simone Dichiara (Penn State University), Tsvetelina Dimitrova (ASU), Alexander Kutyrev (GSFC/UMD), Océlotl López (UNAM), and Margarita Pereyra (UNAM) report: As part of the optical follow-up campaign for LIGO/Virgo/KAGRA S250206dm (LVKC, GCN 39175), the DDOTI/OAN wide-field imager at the Observatorio Astronómico Nacional on Sierra San Pedro Mártir (http://ddoti.astroscu.unam.mx) observed the position RA, Dec = 149.16, -17.94, reported by the IceCube Collaboration as a track-like event spatially and temporally coincident with the gravitational-wave candidate S250206dm (IceCube Collaboration, GCN 39176). DDOTI covered the complete error region reported for this candidate (angular uncertainty of 0.43 deg, IceCube Collaboration, GCN 39176) beginning at 2025-02-07 07:07 UTC (T+9.7 hours after the event). A total exposure of 18 minutes was obtained in the w filter, reaching a 10-sigma limiting magnitude of w = 19.4. Comparing our observations with the USNO-B1 and PanSTARRS PS1 DR2 catalogs, we detect no uncatalogued sources within the observed field to our 10-sigma limit. Observations related to S250206dm are ongoing. We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir. View this GCN Circular online at https://gcn.nasa.gov/circulars/39198. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37206] LIGO/Virgo/KAGRA S250206dm: GOTO observations of optical candidates AT 2025azn and AT 2025azm
by GCN Circulars 07 Feb '25

07 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39197 SUBJECT: LIGO/Virgo/KAGRA S250206dm: GOTO observations of optical candidates AT 2025azn and AT 2025azm DATE: 25/02/07 09:41:10 GMT FROM: kendall.ackley(a)warwick.ac.uk K. Ackley, S. Belkin, D. Steeghs, B. P. Gompertz, Y. Julakanti, M. Kennedy, B. Godson, G. Ramsay, D. O'Neill, M. Dyer, F. Jiménez-Ibarra, J. Lyman, K. Ulaczyk, D. Galloway, V. Dhillon, P. O'Brien, K. Noysena, R. Kotak, R. Breton, L. Nuttall, E. Pallé, D. Pollacco, T. Killestein, and A. Kumar report on behalf of the GOTO collaboration: We are in the process of observing the LIGO/Virgo gravitational wave event S250206dm (GCN 39175; GCN 39178) with the Gravitational-wave Optical Transient Observer (GOTO; Steeghs et al. 2022). Targeted observations with GOTO-N were performed beginning at Feb. 6 2025 21:31:11 UT, (+0.09h post trigger) and continued through to Feb. 7 2025 04:07:48 UT (+6.71h post trigger). GOTO covered the field of AT 2025azn (Hosseinzadeh et al, GCN 39191) at 22:25:45UT on 2025-02-06 (~1 hour after trigger, and 6 hours prior to the reported detection by Hosseinzadeh et al, GCN 39191) as part of the follow-up campaign for S250206dm. The observation consisted of a 4x90s exposure set in the GOTO L-band (400-700 nm). Analysis at the location of the potential optical transient does not show evidence of the source to a 3-sigma limiting AB magnitude of L > 19.8. Our previous observation of the field of AT 2025azm (Hosseinzadeh et al, GCN 39191) occurred on 2025-01-27. We do not see any evidence of excess flux down to a 3-sigma limiting AB magnitude of L > 19.0. Images were processed immediately after acquisition using the GOTO pipeline. Difference imaging was performed using deeper template observations of the same pointings. Source candidates were initially filtered using a classifier (Killestein et al. 2021) and cross-matched against a variety of contextual and minor planet catalogs. Human vetting was carried out in real time on any candidates that passed the above checks. Magnitudes were calibrated using ATLAS-REFCAT2 (Tonry et al. 2018) and are not corrected for Galactic extinction. Further observations are scheduled during the coming nights. GOTO (https://goto-observatory.org) is a network of telescopes that is principally funded by the STFC and operated at the Roque de los Muchachos Observatory on La Palma, Spain, and Siding Spring Observatory in NSW, Australia, on behalf of a consortium including the University of Warwick, Monash University, Armagh Observatory & Planetarium, the University of Leicester, the University of Sheffield, the National Astronomical Research Institute of Thailand (NARIT), the University of Turku, the University of Portsmouth, the University of Manchester and the Instituto de Astrofisica de Canarias (IAC). View this GCN Circular online at https://gcn.nasa.gov/circulars/39197. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37205] LIGO/Virgo/KAGRA S250206dm: SOAR galaxy targeted observations
by GCN Circulars 07 Feb '25

07 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39196 SUBJECT: LIGO/Virgo/KAGRA S250206dm: SOAR galaxy targeted observations DATE: 25/02/07 09:16:25 GMT FROM: Igor Andreoni at JSI/UMD/NASA <igor.andreoni(a)gmail.com> James Freeburn (Swinburne/OzGrav), Jonathan Carney (UNC), Igor Andreoni (UNC), David Cook (IPAC): We followed up the gravitational wave trigger S250206dm (GCN 39175, GCN 39178, GCN 39184) using the Goodman High Throughput Spectrograph mounted on the SOAR telescope in imaging mode via Target of Opportunity observations (PI Andreoni). We observed 33 galaxies in the highest probability region (Cook at al. GCN 39174, GCN 39177, GCN 39185) using the list produced by crossmatching the sky localization with the NED Local Volume Sample (NED-LVS; Cook et al. 2023). Specifically, we considered the galaxy list obtained using the LVK S250206dm-6-Update sky localization (Cook at al. GCN 39185), focusing on the Southern high probability area. Observations were acquired from 2025-02-07 06:18 UT until 08:48 UT. Each galaxy was observed with 60s exposures in g+i filters. A list of the observed galaxies is presented in the table below. The completed pointings were uploaded to TreasureMap: https://treasuremap.space/alerts?graceids=S250206dm Data analysis is ongoing. object_name coordinates WISEA J161708.84-674024.7 16:17:08.87 -67:40:22.49 WISEA J162759.57-693615.7 16:27:59.57 -69:36:15.71 WISEA J154439.56-665529.0 15:44:39.56 -66:55:29.08 WISEA J155633.83-693531.5 15:56:33.83 -69:35:31.55 WISEA J160843.41-685023.4 16:08:43.41 -68:50:23.44 WISEA J154441.36-665502.6 15:44:41.37 -66:55:02.61 WISEA J160915.94-690504.9 16:09:15.95 -69:05:04.94 WISEA J161332.77-674621.1 16:13:32.78 -67:46:21.13 WISEA J165614.58-695645.9 16:56:14.58 -69:56:46.00 WISEA J163330.53-670950.7 16:33:30.54 -67:09:50.72 WISEA J154538.24-703944.1 15:45:38.25 -70:39:44.12 WISEA J153057.77-694546.5 15:30:57.77 -69:45:46.58 WISEA J160838.27-700230.8 16:08:38.27 -70:02:30.85 WISEA J111435.41-485220.0 11:14:35.41 -48:52:20.02 WISEA J161213.79-710729.1 16:12:13.79 -71:07:29.14 ESO 069-IG 006N 16:38:11.94 -68:26:08.84 WISEA J165744.21-680430.9 16:57:44.21 -68:04:30.93 WISEA J165527.54-702337.9 16:55:27.54 -70:23:37.91 WISEA J110452.75-455440.5 11:04:52.76 -45:54:40.57 WISEA J163202.83-693109.0 16:32:02.84 -69:31:09.01 WISEA J164922.44-690054.7 16:49:22.44 -69:00:54.76 WISEA J161735.32-701416.0 16:17:35.32 -70:14:16.00 WISEA J163253.56-702946.2 16:32:53.57 -70:29:46.22 WISEA J164915.17-690004.8 16:49:15.17 -69:00:04.87 ESO 069- G 003 16:24:32.07 -68:49:12.91 WISEA J161946.23-690837.2 16:19:46.23 -69:08:37.26 WISEA J153854.81-680647.5 15:38:54.81 -68:06:47.55 WISEA J151821.27-691417.9 15:18:21.28 -69:14:17.93 WISEA J155653.84-695749.1 15:56:53.88 -69:57:49.18 WISEA J165438.30-670413.8 16:54:38.30 -67:04:13.82 WISEA J163224.97-700239.7 16:32:24.97 -70:02:39.78 WISEA J110509.11-450337.3 11:05:09.11 -45:03:37.38 WISEA J161822.73-683741.1 16:18:22.73 -68:37:41.20 We thank the NOIRLab and SOAR staff for their excellent support. View this GCN Circular online at https://gcn.nasa.gov/circulars/39196. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37204] LIGO/Virgo/KAGRA S250206dm: Pan-STARRS observations of AT2025azm and AT2025azn
by GCN Circulars 07 Feb '25

07 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39195 SUBJECT: LIGO/Virgo/KAGRA S250206dm: Pan-STARRS observations of AT2025azm and AT2025azn DATE: 25/02/07 08:43:10 GMT FROM: James Gillanders at University of Oxford <jhgillanders.astro(a)gmail.com> M. E. Huber (IfA, Hawaii), J. H. Gillanders (Oxford), K. C. Chambers (IfA, Hawaii) S. J. Smartt, K. W. Smith (Oxford/QUB), F. Stoppa, S. Srivastav (Oxford), D. R. Young, M. Nicholl, M. D. Fulton, M. McCollum, T. Moore, S. Sim, J. Weston, A. Aamer, C. R. Angus, X. Sheng (QUB), P. Ramsden (QUB/Birmingham), L. Shingles (GSI/QUB), H. Stevance, A. Andersson (Oxford), L. Rhodes (TSI/McGill), A. S. B. Schultz, T. de Boer, J. Fairlamb, H. Gao, C. C. Lin, T. Lowe, E. Magnier, P. Minguez, G. Paek, A. Smith, R. J. Wainscoat (IfA, Univ. Hawaii), T.-W. Chen (NCU), A. Rest (STScI), and C. Stubbs (Harvard) We are currently observing the skymap of the LIGO/Virgo/KAGRA GW event S250206dm (LVK Collaboration, GCN 39175) with the twin Pan-STARRS telescope system (Chambers et al., 2016, arXiv:1612.05560) and will report detections of candidate optical transients to the TNS, and through GCNs. We also carried out targeted observations of AT2025azm and AT2025azn, two optical counterpart candidates reported by Hosseinzadeh et al., (GCN 39191). The Pan-STARRS system comprises two 1.8-m telescope units located at the summit of Haleakala on the Hawaiian island of Maui, employing an SDSS-like filter system denoted as grizy, and a broad w-filter, which is a composite of the gri-filters. The last Pan-STARRS observations of these fields was 69 days ago for AT2025azm, and 87 days ago for AT2025azn. There are no reliable historical detections at these positions in our database (typical limits of i<21, w<22). There are a few excess flux detections, but these are likely subtraction residuals in the cores of the host galaxies. Our targeted observations consisted of a sequence of 60 second exposures in griz filters for AT2025azm, and grizy filters for AT2025azn. Our observations of AT2025azm commenced at MJD 60713.27593 (2025-02-07 06:37:20.352 UTC), 9.20 hours after the merger event (LVK Collaboration, GCN 39175). Our observations of AT2025azn commenced at MJD 60713.28086 (2025-02-07 06:44:26.477 UTC), 9.31 hours after the merger event. The resultant images were processed with the Pan-STARRS pipeline. After astrometric and photometric calibration, reference images were subtracted from the target stacked images (Magnier et al., 2020a, ApJS, 251, 3; Magnier et al., 2020b, ApJS, 251, 6; Waters et al., 2020, ApJS, 251, 4). We do not detect either transient in any filter. The data were collected in poor seeing conditions (2-3 arcsec), and the 3.5 sigma limits for our 60 second exposures are: AT2025azm: g<20.1, r<20.6, i<19.9, z<19.9 AT2025azn: z<20.2, r<20.7, i<20.3, g<20.7, y<20.4 As we detect no excess flux in any of the difference images, to limits similar to (or deeper than) those reported by Hosseinzadeh et al., (GCN 39191), it suggests to us that they are not real transients. Operation of the Pan-STARRS1 and Pan-STARRS2 telescopes is primarily supported by the National Aeronautics and Space Administration under Grant No. NNX12AR65G and NNX14AM74G, issued through the SSO Near-Earth Object Observations Program. Data processing is enabled by Queen's University Belfast and the University of Oxford, enabled through STFC grants ST/Y001605/1, ST/T000198/1 and ST/X001253/1, the Royal Society, and the Hintze Centre for Astrophysical Surveys. View this GCN Circular online at https://gcn.nasa.gov/circulars/39195. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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