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

[vsnet-grb-info 36877] GRB 250107C: SVOM/GRM observation
by GCN Circulars 09 Jan '25

09 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38870 SUBJECT: GRB 250107C: SVOM/GRM observation DATE: 25/01/09 13:01:24 GMT FROM: Kai <wcxuemail(a)gmail.com> SVOM/GRM team: Wang-Chen Xue, Chen-Wei Wang, Shi-Jie Zheng, Shao-Lin Xiong, Shuang-Nan Zhang (IHEP) report on behalf of the SVOM team: During the commissioning phase, SVOM/GRM was triggered in-flight by a long burst GRB 250107C (SVOM trigger reference: sb25010702) at 2025-01-07T18:52:16.300 UTC (T0), which was also detected by GECAM-B. With the event-by-event data downloaded through the X-band ground station, the GRM light curve shows that this burst consists of multiple pulses with a duration of about 4 s. The SVOM/GRM light curve can be found here: https://www.bursthub.cn//admin/static/svgrb250107C.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: Wang-Chen Xue (IHEP)(xuewc(a)ihep.ac.cn) View this GCN Circular online at https://gcn.nasa.gov/circulars/38870. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 36876] GRB 250101A: Terskol K-800 optical observations
by GCN Circulars 09 Jan '25

09 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38869 SUBJECT: GRB 250101A: Terskol K-800 optical observations DATE: 25/01/09 12:38:39 GMT FROM: Nicolai Pankov at HSE, IKI RAS <colinsergesen(a)gmail.com> N. Pankov (HSE, IKI RAS), A. Pozanenko (IKI RAS), V. Agletdinov (KIAM), A. Moskvitin (SAO RAS) report on behalf of a larger collaboration: We performed optical observations of the field of GRB 250101A (Page et. al, GCN 38752; Li et. al, GCN 38753; Mohan et. al, GCN 38754; Zhu et. al, GCN 38755; Budnev et. al, GCN 38756; Wu et. al, GCN 38758; Zhu et. al, GCN 38759; Goad et. al, GCN 38761; Moskvitin et. al, GCN 38762; Odeh et. al, GCN 38763; Hu et. al, GCN 38764; Moskvitin et. al, GCN 38765; D'Avino et. al, GCN 38768; Escudero-Coca et. al, GCN 38769; Leonini et. al, GCN 38771; Dichiara et. al, GCN 38773; Zhang et. al, GCN 38774; Siegel, GCN 38775; Li et. al, GCN 38776; Komesh et. al, GCN 38777; Ghosh et. al, GCN 38779; Moskvitin et al., GCN 38780; Krimm et. al, GCN 38782; Komesh et. al, GCN 38790; Méndez-Lapido et. al, GCN 38810; Gupta et. al, GCN 38818; Ferro et. al, GCN 38831; Lin et. al, GCN 38837) in the clear light with the 0.8-meter K-800 telescope of the Terskol observatory of INASAN. The observations began on 2025-01-01 18:09:54 UT, i.e. ~0.2 days since trigger. The preliminary photometry of the optical afterglow in the combined image of 160*30 sec is as follows: Date UT start t-T0 Exp. Filter OT Err. UL(3sigma) (mid, days) (s) 2025-01-01 18:09:54 0.22713 160*30 Clear 20.03 0.18 21.5 The photometry is based on nearby stars of PS1 catalog (Lupton transformations) and not corrected for the Galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/38869. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 36875] EP250109a: GOTO optical upper limits
by GCN Circulars 09 Jan '25

09 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38868 SUBJECT: EP250109a: GOTO optical upper limits DATE: 25/01/09 12:35:49 GMT FROM: Amit Kundu at Royal Holloway - UoL/ U of Warwick, UK <amitkundu515(a)gmail.com> A. Kumar, D. O'Neill, G. Ramsay, B. P. Gompertz, R. Starling, M. Kennedy, K. Ackley, M. J. Dyer, J. Lyman, K. Ulaczyk, F. Jimenez-Ibarra, D. Steeghs, D. K. Galloway, V. Dhillon, P. O'Brien, K. Noysena, R. Kotak, R. P. Breton, L. K. Nuttall, E. Palle and D. Pollacco report on behalf of the GOTO collaboration: We report on observations with the Gravitational-wave Optical Transient Observer (GOTO; Steeghs et al. 2022, Dyer et al. 2024) in response to EP-WXT detected EP250109a (Li et al., GCN 38864); also observed by the Swift-XRT (Kennea et al., GCN 38867). Targeted observations were performed using the GOTO-South at 11:42:03 UT on 2025-01-09 (5.401 hours post-trigger). The stacked image is composed of 3x90s exposures in the GOTO L-band (400-700 nm). Images were processed immediately after acquisition using the GOTO pipeline. Difference imaging was performed using deeper template observations of the same pointings. No new optical source within the EP-FXT localisation region (Li et al., GCN 38864) is identified to a 3-sigma limiting magnitude of L > 17.8. The shallower upper limit is attributed to the unfavourable weather conditions at the Siding Spring Observatory (SSO). Magnitudes were calibrated using ATLAS-REFCAT2 (Tonry et al. 2018) and are 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/38868. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 36874] EP250109a: Swift/XRT non-detection
by GCN Circulars 09 Jan '25

09 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38867 SUBJECT: EP250109a: Swift/XRT non-detection DATE: 25/01/09 12:12:58 GMT FROM: Jamie Kennea at Penn State <jak51(a)psu.edu> J. A. Kennea (PSU) and P. A. Evans (Leicester) on behalf of the Swift XRT Team report: On 09:19:41UT Swift XRT began a 950s exposure of the field containing the recently reported transient EP250109a (GCN #38864), 3 hours after detection by Einstein Probe WXT. Examination of the XRT data does not reveal any new X-ray sources, with an upper limit on count rate of 0.01 c/s at the EP FXT position. For a typical GRB-like spectrum this equates to an upper limit on flux of 3 x 10^-13 erg/s/cm^2 (0.3-10 keV). Although GCN #38864 does not report flux, the Swift/XRT non-detection suggests that this transient has rapidly faded. View this GCN Circular online at https://gcn.nasa.gov/circulars/38867. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 36873] GRB 250108A: Swift/UVOT Upper Limits
by GCN Circulars 09 Jan '25

09 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38866 SUBJECT: GRB 250108A: Swift/UVOT Upper Limits DATE: 25/01/09 10:33:26 GMT FROM: Alice Breeveld at MSSL-UCL <a.breeveld(a)ucl.ac.uk> A. A. Breeveld (UCL-MSSL) and N. J. Klingler (GSFC/UMBC/CRESSTII) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of SVOM/ECLAIRs-detected burst GRB 250108A 102468 s after the SVOM trigger (Zheng et al., GCN Circ. 38845). No optical afterglow consistent with either the Swift-XRT proposed X-ray counterpart (Ambrosi et al., GCN Circ. 38853) or the VT optical afterglow candidate (Qiu et al., GCN Circ. 38852), is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the initial exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag w1 102468 109462 2632 >20.9 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.012 in the direction of the burst (Schlegel et al. 1998). View this GCN Circular online at https://gcn.nasa.gov/circulars/38866. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 36872] EP250108a: Global MASTER-Net observations report
by GCN Circulars 09 Jan '25

09 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38865 SUBJECT: EP250108a: Global MASTER-Net observations report DATE: 25/01/09 09:45:53 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 EP250108a ( EP Team et al., GCN 38861) errorbox 731 sec after notice time and 66442 sec after trigger time at 2025-01-09 06:57:50 UT, with upper limit up to 17.9 mag. The observations began at zenith distance = 78 deg. The sun altitude is -27.7 deg. The galactic latitude b = -51 deg., longitude l = 216 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2738908 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 66472 | 2025-01-09 06:57:50 | MASTER-OAFA | (03h 42m 49.01s , -22d 23m 39.2s) | C | 60 | 17.9 | 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/38865. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 36871] EP250109a: EP-WXT detection of an X-ray transient
by GCN Circulars 09 Jan '25

09 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38864 SUBJECT: EP250109a: EP-WXT detection of an X-ray transient DATE: 25/01/09 09:20:17 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> R.-Z. Li (YNAO, CAS), X.-L. Chen (YNU), K. Chatterjee (YNU), Y.-L. Hua (PMO, CAS), H. Sun and Y. Liu (NAO, CAS) report on behalf of the Einstein Probe team: We report on the detection of an X-ray transient detected by EP-WXT, which triggered the on-board processing unit at 2025-01-09 06:17:58 (UTC) (trigger ID: 01709130082). The source position is R.A. = 88.806 deg, DEC = -12.500 deg (J2000) with an uncertainty of about 3 arcmin (radius, 90% C.L. statistical and systematic). A follow-up observation on the X-ray transient was performed by the EP-FXT, which detected an uncatalogued X-ray source at R.A. = 88.8055 deg, DEC = -12.4966 deg (J2000) with an uncertainty of about 20 arcsec (radius, 90% C.L. statistical and systematic), consistent with the position of the WXT transient within the uncertainties. More information will be updated when the telemetry data is received. Further observations are encouraged to explore the origin of the 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/38864. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 36870] LIGO/Virgo/KAGRA S250109bi: Identification of a GW compact binary merger candidate
by GCN Circulars 09 Jan '25

09 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38863 SUBJECT: LIGO/Virgo/KAGRA S250109bi: Identification of a GW compact binary merger candidate DATE: 25/01/09 08:29:17 GMT FROM: davis(a)lpccaen.in2p3.fr The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S250109bi during real-time processing of data from LIGO Hanford Observatory (H1) and Virgo Observatory (V1) at 2025-01-09 07:45:52.379 UTC (GPS time: 1420443970.379). The candidate was found by the GstLAL [1] analysis pipeline. S250109bi is an event of interest because its false alarm rate, as estimated by the online analysis, is 2e-08 Hz, or about one in 1 year, 6 months. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S250109bi After parameter estimation by RapidPE-RIFT [2], the classification of the GW signal, in order of descending probability, is BBH (98%), Terrestrial (2%), 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%. [3] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [3] 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 [4], distributed via GCN notice about 28 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [4], 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 8841 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1246 +/- 386 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] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002 [3] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [4] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013 View this GCN Circular online at https://gcn.nasa.gov/circulars/38863. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 36869] GRB 250108A: NOT optical upper limit
by GCN Circulars 09 Jan '25

09 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38862 SUBJECT: GRB 250108A: NOT optical upper limit DATE: 25/01/09 07:58:40 GMT FROM: Daniele B. Malesani at IMAPP / Radboud University <d.malesani(a)astro.ru.nl> S. De Wet (DTU Space), D. B. Malesani (DAWN/NBI and Radboud), L. Izzo (INAF/OACn and DARK/NBI), D. Xu (NAOC), S. Grund Sorensen (NOT and Aarhus), N. Pyykkinen (NOT and Turku) report on behalf of a larger collaboration: We observed the field of the SVOM GRB 250108A (Zheng et al., GRB 38845) using the Nordic Optical Telescope (NOT) equipped with ALFOSC. The observations were carried out in the z band, with a mid time 2025 Jan 9.14 UT (22.72 hr after the GRB), and for a total exposure time of 2000 s. In the stack of our images, we do not detect any source at either the position of the VT optical afterglow candidate (Qiu et al., GCN 38852), nor within the Swift/XRT localization region of the proposed X-ray counterpart (Ambrosi et al., GCN 38853). The limiting magnitude is approximately z > 22.1 (AB), calibrated against nearby stars from the Pan-STARRS catalog. View this GCN Circular online at https://gcn.nasa.gov/circulars/38862. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 36868] EP250108a: EP-WXT detection of an X-ray transient
by GCN Circulars 09 Jan '25

09 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38861 SUBJECT: EP250108a: EP-WXT detection of an X-ray transient DATE: 25/01/09 06:41:37 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> R.-Z. Li (YNAO, CAS), X.-L. Chen (YNU), K. Chatterjee (YNU), Y.-L. Hua (PMO) and Y. Liu (NAOC) report on behalf of the Einstein Probe team: We report on the detection of an X-ray transient, designated EP250108a, by the Wide-field X-ray Telescope (WXT, trigger ID: 06800000356) on board the Einstein Probe (EP) mission. The transient event was detected at 2025-01-08T12:30:28.34 (UTC). The WXT position of the source is R.A. = 55.623 deg, DEC = -22.509 deg (J2000) with an uncertainty of 2.2 arcmin in radius (90% C.L. statistical and systematic). The transient event lasts for about 2500 seconds. The peak flux in the 0.5-4 keV is around 1.4 x 10^-10 erg/s/cm^2. The average 0.5-4 keV spectrum can be fitted with an absorbed power law with a photon index of 1.35 +/- 0.40 (with a Galactic column density fixed at 1.6 x 10^20 cm^-2). The derived average unabsorbed 0.5-4 keV flux is 4.2 (+1.2/-0.9) x 10^-11 erg/s/cm^2. The uncertainties are at the 90% confidence level for the above parameters. A follow-up observation with the Follow-up X-ray Telescope (FXT) on board EP has been scheduled. Further observations are encouraged to explore the origin of the 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). EP is a mission of the Chinese Academy of Sciences in collaboration with ESA, MPE and CNES. View this GCN Circular online at https://gcn.nasa.gov/circulars/38861. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

2025

2024

2023

2022

2021

vsnet-grb-info January 2025