February 2025 - vsnet-grb-info - ooruri.kusastro.kyoto-u.ac.jp

[vsnet-grb-info 37306] LIGO/Virgo/KAGRA S250206dm: GECKO Continued Observaiton with 7DT
by GCN Circulars 12 Feb '25

12 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39297 SUBJECT: LIGO/Virgo/KAGRA S250206dm: GECKO Continued Observaiton with 7DT DATE: 25/02/12 02:15:38 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 (… [View More]LVK) gravitational-wave (GW) event, S250206dm (LVK Collaboration, GCN 39175) with the 7-Dimensional Telescope (7DT) following previous report (Paek et al., GCN 39241). Observations with the 7DT array began on 2025-02-07 at 01:24 UT, roughly four hours after the GW event. Pre-defined tiles were chosen to overlap with the 90% credible region of the GW skymap, and a wide-field search strategy was implemented by assigning each telescope a distinct sky area to maximize coverage. Thirteen 7DT units were employed to sequentially image the region—initially in the g-band and subsequently in the r-band. Per-tile exposure times ranged from 3*100 seconds to 6*100 seconds. Over the two observing epochs from 2025-02-07 (UT) to 2025-02-08 (UT), our observations covered a total of 590 tiles (~590 deg2) in the g-band and 320 tiles (~320 deg2) in the r-band. The achieved 5-sigma depth varied by band, reaching 19.0–21.7 mag in the g-band and 18.4–21.2 mag in the r-band. Notably, following the initial g-band and r-band imaging, two additional epochs of g-band exposures are planned for the updated GW skymap region (LVK Collaboration, GCN 39231)—covering 75 tiles—in coordination with KMTNet’s R- and I-band imaging to ensure comprehensive multi-color coverage. Additionally, a dedicated transient search is scheduled for forthcoming analysis. The coverage of observations is detailed in TreasureMap (Wyatt et al. 2020; https://treasuremap.space/alerts?graceids=S250206dm). The 7-Dimensional Telescope (7DT), located in Chile and comprising 20 wide-field telescopes equipped with 40 medium-bandwidth (~25nm) filters, aims to detect optical counterparts of GW sources and conduct the 7-Dimensional Sky Survey (7DS) of the Southern Hemisphere. Further information about the 7DT is available at https://7ds.snu.ac.kr/ and http://gwuniverse.snu.ac.kr/. View this GCN Circular online at https://gcn.nasa.gov/circulars/39297. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L… [View Less]

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[vsnet-grb-info 37305] GRB 250211A: Swift ToO observations
by GCN Circulars 12 Feb '25

12 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39296 SUBJECT: GRB 250211A: Swift ToO observations DATE: 25/02/12 01:52:54 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 ToO observation of the SVOM/ECLAIRs GRB 250211A. Automated analysis of the XRT data will be presented online at https://www.swift.ac.uk/ToO_GRBs/00021776 Any uncatalogued X-ray sources detected in this analysis will be reported … [View More]

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[vsnet-grb-info 37304] Integral GRB250211.89: Global MASTER-Net observations report
by GCN Circulars 12 Feb '25

12 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39295 SUBJECT: Integral GRB250211.89: Global MASTER-Net observations report DATE: 25/02/12 01:19:50 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. … [View More]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) was pointed to the Integral GRB250211.89 (trigger No 11044,18h 25m 33.49s , -31d 57m 36.2s, R=0.0533333) errorbox 12195 sec after notice time and 12210 sec after trigger time at 2025-02-12 00:51:28 UT, with upper limit up to 16.7 mag. The observations began at zenith distance = 81 deg. The sun altitude is -36.1 deg. The galactic latitude b = -10 deg., longitude l = 2 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2775663 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 12300 | MASTER-SAAO | C | 180 | 16.1 | 12480 | MASTER-SAAO | C | 540 | 15.8 | Coadd 12500 | MASTER-SAAO | C | 180 | 16.2 | 12699 | MASTER-SAAO | C | 180 | 16.4 | 12904 | MASTER-SAAO | C | 180 | 16.4 | 13103 | MASTER-SAAO | C | 180 | 16.5 | 13302 | MASTER-SAAO | C | 180 | 16.6 | 13502 | MASTER-SAAO | C | 180 | 16.7 | 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/39295. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L… [View Less]

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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 =… [View More]

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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-… [View More]

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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 (… [View More]

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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 … [View More]

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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. … [View More]

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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 (… [View More]

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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: … [View More]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… [View Less]

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