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

[vsnet-grb-info 41614] GRB 260125A: GOTO candidate optical counterpart
by GCN Circulars 25 Jan '26

25 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43514 SUBJECT: GRB 260125A: GOTO candidate optical counterpart DATE: 26/01/25 20:20:30 GMT FROM: Ben Gompertz at U of Birmingham <b.gompertz(a)bham.ac.uk> B. P. Gompertz, S. Moran, D. O’Neill, R. Starling, K. Ackley, M. Dyer, J. Lyman, K. Ulaczyk, D. Steeghs, D. Galloway, V. Dhillon, P. O'Brien, G. Ramsay, K. Noysena, R. Kotak, R. Breton, J. Casares, L. Nuttall, B. Godson, T. Killestein, A. Kumar, M. Pursiainen report on behalf of GOTO collaboration: We report on optical observations with the Gravitational-wave Optical Transient Observer (GOTO; Steeghs et al. 2022, Dyer et al. 2024) in response to the GRB 260125A (Fermi GBM Team, GCN 43510). Observations from GOTO-South (Siding Spring) covering the localisation area began at 2026-01-25 12:06:29 UT (+4.49h post trigger) and continued through to 2026-01-25 15:46:04 UT (+8.54h post trigger). 292 images were taken, across 16 unique pointings, covering 510.2 within the 90% localisation contour. ~78.0% of the total 2D localisation probability was covered, with an average 5-sigma depth of 20.8 mag. Images were processed immediately after acquisition using the GOTO pipeline. 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. Within the 90% probability region, we identify a new transient, GOTO26acv (AT 2026bjf), lying on the 20th percentile contour of the GBM localisation map at coordinates: RA = 10:06:16.71, Dec = -06:34:33.55 (J2000), equivalent to RA = 151.56962, Dec = -6.57599 degrees. GOTO26acv / AT 2026bjf was discovered with an AB magnitude of L = 20.17 ± 0.16 in an epoch taken at 12:29:25 UT, i.e. 4.87h post-trigger. Across three epochs of detection, it was observed to fade by 0.42 ± 0.25 magnitudes in 2.35 hours, equivalent to a power-law decay rate of t^-0.92 ± 0.38. The final detection magnitude was L = 20.59 ± 0.19 at 14:50:26 UT. The source is spatially coincident with the galaxy PGC 139241 at a luminosity distance of 53 Mpc. It is offset from the nucleus by ~9”. The source was not present in the most recent survey image of the field, taken at 13:37:58 UT on 2026-01-24 (0.75 days prior to the GRB trigger), to a 3-sigma limiting magnitude of L > 20.95. We also find no evidence of GOTO26acv / AT 2026bjf prior to the GRB trigger time in the ZTF observations provided by the Lasair broker (Smith et al. 2019), or the ATLAS forced photometry server (Shingles et al. 2021). Further follow-up observations to establish the nature of GOTO26acv / AT2026bjf and its potential association with GRB 260125A are encouraged. 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, the University of Birmingham and the Instituto de Astrofisica de Canarias (IAC). View this GCN Circular online at https://gcn.nasa.gov/circulars/43514. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41613] Fermi GRB 260125B: Global MASTER-Net observations report
by GCN Circulars 25 Jan '26

25 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43513 SUBJECT: Fermi GRB 260125B: Global MASTER-Net observations report DATE: 26/01/25 11:45:33 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, A.Kuznetsov, K.Zhirkov, I.Panchenko, N.Tiurina, P.Balanutsa, V.Topolev, D.Vlasenko, G.Antipov, A.Sankovich, Yu.Tselik, 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.Sosnovskij (CrAO), 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-Tunka robotic telescope [1] located in Russia (Applied Physics Institute, Irkutsk State University) started inspect of the Fermi GRB 260125B ( Fermi GBM team, GCN 43511) errorbox 3759 sec after notice time and 3791 sec after trigger time at 2026-01-25 11:28:56 UT, with upper limit up to 18.4 mag. Observations started at twilight. The observations began at zenith distance = 43 deg. The sun altitude is -16.2 deg. The galactic latitude b = -13 deg., longitude l = 185 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3114740 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 3821 | 2026-01-25 11:28:56 | MASTER-Tunka | (05h 18m 03.87s , +20d 44m 22.3s) | C | 60 | 18.4 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. [1] - V.M. Lipunov, V.G. Kornilov, E.S. Gorbovskoy, N.A. Tiurina & A.S.Kuznetsov, 2023, Astronomical Robotic Networks and Operative Multichanel Astrophysics, Lomonosov MSU PRESS, 591pp. http : // www.pereplet.ru/lipunov/625.html View this GCN Circular online at https://gcn.nasa.gov/circulars/43513. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41612] Fermi GRB 260125B: Global MASTER-Net observations report
by GCN Circulars 25 Jan '26

25 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43513 SUBJECT: Fermi GRB 260125B: Global MASTER-Net observations report DATE: 26/01/25 11:45:33 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, A.Kuznetsov, K.Zhirkov, I.Panchenko, N.Tiurina, P.Balanutsa, V.Topolev, D.Vlasenko, G.Antipov, A.Sankovich, Yu.Tselik, 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.Sosnovskij (CrAO), 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-Tunka robotic telescope [1] located in Russia (Applied Physics Institute, Irkutsk State University) started inspect of the Fermi GRB 260125B ( Fermi GBM team, GCN 43511) errorbox 3759 sec after notice time and 3791 sec after trigger time at 2026-01-25 11:28:56 UT, with upper limit up to 18.4 mag. Observations started at twilight. The observations began at zenith distance = 43 deg. The sun altitude is -16.2 deg. The galactic latitude b = -13 deg., longitude l = 185 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3114740 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 3821 | 2026-01-25 11:28:56 | MASTER-Tunka | (05h 18m 03.87s , +20d 44m 22.3s) | C | 60 | 18.4 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. [1] - V.M. Lipunov, V.G. Kornilov, E.S. Gorbovskoy, N.A. Tiurina & A.S.Kuznetsov, 2023, Astronomical Robotic Networks and Operative Multichanel Astrophysics, Lomonosov MSU PRESS, 591pp. http : // www.pereplet.ru/lipunov/625.html View this GCN Circular online at https://gcn.nasa.gov/circulars/43513. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41611] IceCube-260125A - IceCube observation of a high-energy neutrino candidate track-like event
by GCN Circulars 25 Jan '26

25 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43512 SUBJECT: IceCube-260125A - IceCube observation of a high-energy neutrino candidate track-like event DATE: 26/01/25 11:33:55 GMT FROM: A. Zegarelli at Ruhr University Bochum <azegarelli(a)icecube.wisc.edu> The IceCube Collaboration (http://icecube.wisc.edu/) reports: On 26-01-25 at 10:09:39.88 UT IceCube detected a track-like event with a moderate 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 1.9783 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/141985_63695019.amon) more sophisticated reconstruction algorithms have been applied offline, with the direction refined to: Date: 26-01-25 Time: 10:09:39.88 UT RA: 243.72 (+0.52/-0.56 deg 90% PSF containment) J2000 Dec: 6.69 (+0.62/-0.61 deg 90% PSF containment) J2000 As announced in GCN Circular 43419, IceCube alert notices for high-energy track alerts are now also streamed via Kafka. IceCube Gold/Bronze track alerts are available on the Kafka topic 'gcn.notices.icecube.gold_bronze_track_alerts'. The probability distribution of the true neutrino direction, allowing the extraction of precise 90% containment regions around the best-fit direction, is now available for revised reconstruction of high-energy track alerts. The corresponding sky map is distributed as a FITS file and follows the explicit naming convention IceCube-YYMMDDX (e.g. IceCube-260125A, for this alert), where YYMMDD indicates the date of the event and X is a letter distinguishing multiple alerts on the same day. The download link (e.g., for this alert https://roc-2.icecube.wisc.edu/public/alerts/IceCube-260125A_skymap_probden…) is provided through the GCN schema distributed via Kafka. Additional information will be soon available at https://gcn.nasa.gov/missions/icecube. In the near future, classical GCN stream will be deactivated. No known gamma-ray sources listed in the Fermi 4FGL-DR4 or 3FHL catalogs are located within the 90% uncertainty region of this event. 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/43512. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41610] GRB 260125B: Fermi GBM Final Real-time Localization
by GCN Circulars 25 Jan '26

25 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43511 SUBJECT: GRB 260125B: Fermi GBM Final Real-time Localization DATE: 26/01/25 10:36:26 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 10:25:45 UT on 25 Jan 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260125B (trigger 791029550.226442 / 260125435). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 77.1, Dec = 17.6 (J2000 degrees, equivalent to J2000 05h 08m, 17d 36'), with a statistical uncertainty of 11.6 degrees. The angle from the Fermi LAT boresight is 28.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260125435/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260125435/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260125435/… View this GCN Circular online at https://gcn.nasa.gov/circulars/43511. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41609] GRB 260125A: Fermi GBM Final Real-time Localization
by GCN Circulars 25 Jan '26

25 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43510 SUBJECT: GRB 260125A: Fermi GBM Final Real-time Localization DATE: 26/01/25 07:47:31 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 07:36:58 UT on 25 Jan 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260125A (trigger 791019423.079276 / 260125317). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 148.7, Dec = -2.9 (J2000 degrees, equivalent to J2000 09h 54m, -2d 53'), with a statistical uncertainty of 8.9 degrees. The angle from the Fermi LAT boresight is 67.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260125317/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260125317/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260125317/… View this GCN Circular online at https://gcn.nasa.gov/circulars/43510. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41608] GRB 260114A: SVOM/VT optical upper limits
by GCN Circulars 25 Jan '26

25 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43509 SUBJECT: GRB 260114A: SVOM/VT optical upper limits DATE: 26/01/25 04:16:37 GMT FROM: Yinuo Ma <mayn(a)bao.ac.cn> Y. N. Ma (NAOC), R. Z. Li (YNAO), L. P. Xin, H. L. Li, Z. H. Yao, Y. L. Qiu, C. Wu, X. H. Han, Y. Xu, J. Wang, P. P. Zhang, W. J. Xie, Y. J. Xiao, H. B. Cai, L. Lan, J. S. Deng, J. Y. Wei, D. H. Zhao (NAOC), J. Palmerio (CEA), B. T. Wang (YNAO), Y. H. Cheng (YNU) report on behalf of the SVOM/VT team. SVOM/VT performed a Target of Opportunity observation of GRB 260114A detected by Swift/BAT, Fermi/GBM, SVOM/GRM, GECAM-B, Konus-Wind and Insight-HXMT/HE (Fermi GBM Team, GCN 43395; Eyles-Ferris et al., GCN 43396; Bissaldi, GCN 43400; Ren et al., GCN 43402; Wang et al., GCN 43404; Beardmore et al., GCN 43412; Ridnaia et al., GCN 43413; Ren et al., GCN 43503). SVOM/VT began observing the field at 2026-01-14 14:47:02 UTC, 3.11 hours after T0, in the VT_B (400nm-650nm) and VT_R (650nm-1000nm) channels simultaneously. We performed the second observation as a template on January 19th. After performing image subtraction of our stacked images against the second observation, no uncataloged candidate was detected within the error box provided by Swift/XRT position (Beardmore et al., GCN 43412) or the optical counterpart previously reported by GMG (Li et al., GCN Circ. 43398) and the Mondy observatory (Volnova et al., GCN Circ. 43401). The three sigma limits are: mid-time | exposure time | band | upper limit (AB) ----------|-----------------|-------|----------------- 4.241 h | 69*70 sec | VT_B | > 23.8 mag 4.251 h | 67*70 sec | VT_R | > 23.5 mag Our results are consistent with MASTER (Lipunov et al., GCN Circ. 43403), NOT (Corcoran et al., GCN Circ. 43406), TNG (Brivio et al., GCN Circ. 43407), COLIBRÍ (Angulo et al., GCN 43408), MITSuME (Takahashi et al., GCN 43409), VLT (Yang et al., GCN 43414; Schneider et al ., GCN 43423) and Swift/UVOT (Siegel & Eyles-Ferris, GCN 43473). 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. VT was jointly developed by Xi'an Institute of Optics and Precision Mechanics (XIOPM), CAS and National astronomical observatories (NAOC), CAS. View this GCN Circular online at https://gcn.nasa.gov/circulars/43509. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41607] GRB 260120A: AstroSat CZTI detection
by GCN Circulars 24 Jan '26

24 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43508 SUBJECT: GRB 260120A: AstroSat CZTI detection DATE: 26/01/24 11:33:06 GMT FROM: Anuraag Arya at IIT Bombay <aryaanuraag910(a)gmail.com> Harsha K. H. (IUCAA), M. Tembhurnikar (IUCAA), S. Salunke (IUCAA), A. Arya (IITB), A. Goyal (IITB), G. Waratkar (Caltech/IITB), 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 GRB 260120A which was also detected by Fermi GBM (Fermi GBM Team, GCN Circ. 43467), and GECAM-B (Guo et al., GCN Circ. 43505). The source was clearly detected in the CZT detectors in the 20-200 keV energy range. The light curve peaks at 2026-01-20 04:01:55.50 UTC. The measured peak count rate associated with the burst is 264 (+132, -24) counts/s above the background in the combined data of three quadrants (out of four), with a total of 345 (+83, -77) counts. The local mean background count rate was 189 (+3, -7) counts/s. Using cumulative rates, we measure a T90 of 3.1 (+1.1, -0.8) s. The source was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2026-01-20 04:01:54.79 UTC. The measured peak count rate associated with the burst is 246 (+62, -64) counts/s above the background in the combined data of all quadrants, with a total of 625 (+185, -199) counts. The local mean background count rate was 1120 (+5, -6) counts/s. We measure a T90 of 4.2 (+1.3, -1.5) s from the cumulative Veto light curve. 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/43508. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41606] GRB 260122B: Swift-BAT refined analysis
by GCN Circulars 24 Jan '26

24 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43507 SUBJECT: GRB 260122B: Swift-BAT refined analysis DATE: 26/01/24 00:54:15 GMT FROM: Amy <yarleen(a)gmail.com> D. M. Palmer (LANL), S. D. Barthelmy (GSFC), R. Gupta (GSFC), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa), C. B. Markwardt (GSFC), A. Mei (INAF-OAB), M. J. Moss (GSFC), T. Parsotan (GSFC), D. Sadaula (GSFC/UMBC), T. Sakamoto (AGU) (i.e. the Swift-BAT team): Using the data set from T-60 to T+243 sec from the recent telemetry downlink, we report further analysis of BAT GRB 260122B (trigger #1443066) (Mei et al., GCN Circ. 43502). The ground analysis confirms that this event is indeed a GRB and not due to background fluctuations (Mei et al., GCN Circ. 43502). The BAT ground-calculated position is RA, Dec = 336.096, -59.176 deg which is RA(J2000) = 22h 24m 22.9s Dec(J2000) = -59d 10' 32.1" with an uncertainty of 1.6 arcmin, (radius, sys+stat, 90% containment). The partial coding was 57%. The mask-weighted light curve shows a single-pulse structure that starts ~T-1 s, peaks at ~T+9 s, and ends at ~T+20 s. T90 (15-350 keV) is 16.59 +- 3.89 sec (estimated error including systematics). The time-averaged spectrum from T+0.23 to T+19.51 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.34 +- 0.17. The fluence in the 15-150 keV band is 1.0 +- 0.1 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from T+8.46 sec in the 15-150 keV band is 1.6 +- 0.3 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/1443066 View this GCN Circular online at https://gcn.nasa.gov/circulars/43507. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41605] GRB 260120B: SVOM/GRM observation
by GCN Circulars 23 Jan '26

23 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43506 SUBJECT: GRB 260120B: SVOM/GRM observation DATE: 26/01/23 15:57:20 GMT FROM: renyz16607(a)163.com SVOM/GRM team: Yang-Zhao Ren, Chen-Wei Wang, Shi-Jie Zheng, Yue Huang, Shao-Lin Xiong, Shuang-Nan Zhang (IHEP) SVOM/ECLAIRs team: Sebastien Guillot(IRAP) Report on behalf of the SVOM team: SVOM/GRM was triggered on-ground by GRB 260120B at 2026-01-20T18:00:26.200 UTC (T0), which is also detected by Fermi/GBM (Fermi GBM Team, GCN #43477) and Swift/BAT (Ferro et al., GCN #43479). With the event-by-event data downloaded through the X-band ground station, the GRM light curve shows that this burst consists of a pulse with a T90 of 8.5 +5.0/-3.5 s in the 15-5000 keV band. The SVOM/GRM light curve can be found here: https://www.bursthub.cn//admin/static/svgrb260120B.png In addition, the position of this burst, as determined by Swift/BAT (RA = 284.666, Dec = 61.912, GCN #43479), is located at about 89 degrees from the SVOM optical axis, which is outside the ECLAIRs field of view. With this localization, the time-averaged spectrum from T0 to T0+5 s is best fitted by a power law function with an exponential high-energy cutoff. The power law index is -1.16 +0.16/-0.18 and the cutoff energy, parameterized as Epeak, is 307 +106/-62 keV. The event fluence (10-1000 keV) in this time interval is (3.78 +0.32/-0.33)E-06 erg/cm^2. The localization of GRB 260120B in the 'Amati' relation diagram is shown at: https://www.bursthub.cn//admin/static/svgrb260120B_amati.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 point of contact for this burst is: Yang-Zhao Ren (IHEP)(renyz(a)ihep.ac.cn) View this GCN Circular online at https://gcn.nasa.gov/circulars/43506. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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