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

[vsnet-grb-info 36797] GRB 250103A: Xinglong 2.16m Optical Candidate
by GCN Circulars 03 Jan '25

03 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38795 SUBJECT: GRB 250103A: Xinglong 2.16m Optical Candidate DATE: 25/01/03 14:18:28 GMT FROM: Rui-Zhi Li at Yunnan Observatories, CAS <liruizhi(a)ynao.ac.cn> R.-Z. Li, B.-T. Wang, J. Mao (YNAO, CAS), L. P. XIN, J. Y. Wei, H. L. Li, Y. L. Qiu, J. Wang, C. Wu, X. H. Han (NAOC), J. X. Cao, D. F. Kong (GXU) and Y. Wang (PMO, CAS) report on behalf of SVOM team: We observed the field of GRB 250103A (Wang et al., GCN 38786) using the 2.16m telescope at the Xinglong Observatory, China. The observation began at 2025-01-03T11:41:12 UTC, about 1.74 hours after the trigger. 5*200 sec I-band images were obtained. An uncataloged bright source was detected in I-band images within the error box of SVOM/ECLAIR (Wang et al., GCN 38786), compared to Pan-STARRS1 image. The coordinates (J2000): R.A. = 01:28:15.29 DEC. = -05:03:06.4 with an uncertainty of 0.5 arcseconds. The preliminary analysis results are shown as follows: +-------------------+------------+----------+--------------+----------------+ | Tstart (UTC) | Exp. [s] | Filter | Mag | 5-sigma U.L. | +===================+============+==========+==============+================+ |2025-01-03T11:41:12| 5*200 | I | 19.49 ± 0.04 | 21.5 | +-------------------+------------+----------+--------------+----------------+ We propose it is the candidate of the burst. More follow-ups are encouraged to confirm the nature of the source. The given magnitudes are derived based on calibration against Pan-STARRS1 field stars, and are not corrected for the expected Galactic foreground extinction, corresponding to a reddening of E(B-V) = 0.0362 mag in the direction of the optical counterpart (Schlafly & Finkbeiner 2011). View this GCN Circular online at https://gcn.nasa.gov/circulars/38795. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36796] Fermi GRB 250102A: Global MASTER-Net observations report
by GCN Circulars 03 Jan '25

03 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38794 SUBJECT: Fermi GRB 250102A: Global MASTER-Net observations report DATE: 25/01/03 14:15:28 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-Kislovodsk robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) started inspect of the Fermi GRB 250102A ( Fermi GBM team, GCN 38784) errorbox 1044 sec after notice time and 1077 sec after trigger time at 2025-01-02 22:56:02 UT, with upper limit up to 14.5 mag. The observations began at zenith distance = 90 deg. The sun altitude is -61.0 deg. The galactic latitude b = -15 deg., longitude l = 100 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2731859 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 1168 | 2025-01-02 22:56:02 | MASTER-Kislovodsk | (22h 42m 00.60s , +42d 07m 23.8s) | P- | 180 | 14.5 | 1368 | 2025-01-02 22:59:22 | MASTER-Kislovodsk | (22h 42m 00.83s , +42d 07m 15.1s) | P- | 180 | 14.3 | 1567 | 2025-01-02 23:02:42 | MASTER-Kislovodsk | (22h 41m 56.18s , +42d 08m 00.6s) | P- | 180 | 14.3 | 1767 | 2025-01-02 23:06:02 | MASTER-Kislovodsk | (22h 41m 56.07s , +42d 07m 44.4s) | P- | 180 | 14.1 | 15978 | 2025-01-03 03:03:53 | MASTER-Kislovodsk | (22h 41m 48.44s , +42d 16m 25.5s) | C | 60 | 14.3 | 16138 | 2025-01-03 03:06:33 | MASTER-Kislovodsk | (22h 41m 48.71s , +42d 15m 15.3s) | C | 60 | 14.4 | 16218 | 2025-01-03 03:07:53 | MASTER-Kislovodsk | (22h 41m 44.74s , +42d 16m 45.8s) | C | 60 | 13.9 | 16298 | 2025-01-03 03:09:13 | MASTER-Kislovodsk | (22h 41m 45.28s , +42d 14m 55.4s) | C | 60 | 13.9 | 16378 | 2025-01-03 03:10:33 | MASTER-Kislovodsk | (22h 41m 49.42s , +42d 16m 49.3s) | C | 60 | 14.3 | 16458 | 2025-01-03 03:11:53 | MASTER-Kislovodsk | (22h 41m 42.71s , +42d 15m 49.3s) | C | 60 | 14.1 | 16861 | 2025-01-03 03:18:35 | MASTER-Kislovodsk | (22h 41m 43.84s , +42d 17m 07.6s) | C | 60 | 14.5 | 16940 | 2025-01-03 03:19:55 | MASTER-Kislovodsk | (22h 41m 49.01s , +42d 16m 04.5s) | C | 60 | 14.4 | 17624 | 2025-01-03 03:31:19 | MASTER-Kislovodsk | (22h 41m 48.01s , +42d 15m 31.1s) | C | 60 | 14.5 | 17704 | 2025-01-03 03:32:38 | MASTER-Kislovodsk | (22h 41m 51.23s , +42d 17m 11.4s) | C | 60 | 14.4 | 17784 | 2025-01-03 03:33:58 | MASTER-Kislovodsk | (22h 41m 41.00s , +42d 16m 19.6s) | C | 60 | 12.4 | 17943 | 2025-01-03 03:36:38 | MASTER-Kislovodsk | (22h 41m 53.78s , +42d 16m 10.6s) | C | 60 | 13.7 | 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/38794. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36795] GRB 250101B: SVOM/GRM observation
by GCN Circulars 03 Jan '25

03 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38793 SUBJECT: GRB 250101B: SVOM/GRM observation DATE: 25/01/03 13:31:25 GMT FROM: wenlongzhang2018(a)163.com SVOM/GRM team: Wen-Long Zhang, Wen-Jun Tan, 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 detected GRB 250101B at 2025-01-01T23:14:12 UT (T0), which was also observed by Fermi/GBM (Fermi GBM Team, GCN 38766). With the event-by-event data downloaded through the X-band ground station, the GRM light curve shows that this burst consists of two main pulses with a T90 of 5.27 +/-1.24 s. This burst is located (from Fermi/GBM) at about 96.02 degrees from the SVOM optical axis, and outside the ECLAIRs field of view. The GRM light curve can be found here: https://www.bursthub.cn//admin/static/svgrb250101B.png The Space Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA), French Space Agency (CNES), and the Chinese Academy of Sciences (CAS), 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: Wen-Long Zhang (IHEP)(zhangwl(a)ihep.ac.cn) View this GCN Circular online at https://gcn.nasa.gov/circulars/38793. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36794] GRB 250103A: GOTO optical upper limit
by GCN Circulars 03 Jan '25

03 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38792 SUBJECT: GRB 250103A: GOTO optical upper limit DATE: 25/01/03 13:19:30 GMT FROM: Rhaana Starling at U of Leicester <rlcs1(a)leicester.ac.uk> R. Starling, D. O’Neill, A. Kumar, B. Godson, B. P. Gompertz, K. Ackley, M. J. Dyer, J. Lyman, K. Ulaczyk, F. Jimenez-Ibarra, D. Steeghs, D. K. Galloway, V. Dhillon, P. O'Brien, G. Ramsay, K. Noysena, R. Kotak, R. P. Breton, L. K. Nuttall, E. Palle and D. Pollacco report on behalf of the GOTO collaboration: The Gravitational-wave Optical Transient Observer (GOTO; Steeghs et al. 2022, Dyer et al. 2024) serendipitously covered the field of SVOM-triggered GRB 250103A (Wang et al. GCN 38787) at 11:06:02 UT on 2025-01-03 (1.17 hours after the trigger). The observation was taken by GOTO-South, and consisted of 4x90s 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. Source candidates were initially filtered using a classifier (Killestein et al. 2021) and cross-matched against a variety of contextual and minor planet catalogues. We do not identify any candidate optical counterparts within the SVOM localisation uncertainty region, down to a 3-sigma limiting magnitude of L > 19.8, consistent with the non-detection reported by Wu et al. (GCN 38791). 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/38792. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36793] GRB 250103A: SVOM/C-GFT optical upper limit
by GCN Circulars 03 Jan '25

03 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38791 SUBJECT: GRB 250103A: SVOM/C-GFT optical upper limit DATE: 25/01/03 13:07:47 GMT FROM: Chao Wu at NAOC <cwu(a)nao.cas.cn> SVOM/C-GFT team: Chao WU (NAOC), Zhe Kang (CHO), Liping Xin(NAOC),Yulei Qiu (NAOC), Xuhui Han(NAOC), Pinpin Zhang (NAOC), Xiaomeng Lu (NAOC), Zhenwei Li (CHO), You Lv (CHO), Ruosong Zhang (NAOC), Yujie Xiao(NAOC) SVOM JSWG: Jian-Yan Wei (NAOC), Bertrand Cordier (CEA), Shuang-Nan Zhang (IHEP), Stéphane Basa (LAM), Arnaud Claret (CEA), Zi-Gao Dai (USTC), Frédéric Daigne (IAP), Jin-Song Deng (NAOC),Olivier Godet (IRAP), Andrea Goldwurm (APC), Diego Götz (CEA), Xu-Hui Han (NAOC), Cyril Lachaud (APC), En-Wei Liang (GXU), Yu-Lei Qiu (NAOC), Susanna Vergani (Obs.Paris), Jing Wang (NAOC), Chao Wu (NAOC), Li-Ping Xin (NAOC), Shao-Lin Xiong (IHEP), Bing Zhang (UNLV) We observed the field of GRB 250103A (Wang et al., GCN 38787) starting at 2025-01-03T09:57:26, ~83 sec after the burst trigger with C-GFT. A series of g,r,i band images were obtained with exposure time of 10s for each frame. No any uncataloged sources were detected within the SVOM/ECLAIRs error circle (Wang et al., GCN 38787) compared to PanSTARRS1 catalog. 3 sigma limit magnitude of i=19.4 was derived at the middle time of ~120 s after the trigger. We thank the observation assistant Guangsheng Zhang and Yinhuai Hao at Jilin observatory for their excellent support. Chinese Ground Follow-up Telescope of SVOM mission is located at Jilin, Changchun Observatory, National Astronomical Observatories, CAS. It has FOV of 1.28 deg x 1.28 deg with a 4k*4k CMOS detector mounted on the primary focus of 1.2-meter-aperure telescope. View this GCN Circular online at https://gcn.nasa.gov/circulars/38791. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36792] GRB 250101A: NUTTelA-TAO / BSTI Optical Limits
by GCN Circulars 03 Jan '25

03 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38790 SUBJECT: GRB 250101A: NUTTelA-TAO / BSTI Optical Limits DATE: 25/01/03 12:16:34 GMT FROM: Toktarkhan Komesh at Nazarbayev University <toktarkhan.komesh(a)nu.edu.kz> T. Komesh (NU), Z. Maksut (NU), Z. Abdullayev (NU), B. Grossan (UCB, NU), D. Berdikhan (NU), M. Krugov (FAI) and E. Abdikamalov (NU) report on behalf of the Energetic Cosmos Laboratory: The Nazarbayev University Transient Telescope at Assy-Turgen Astrophysical Observatory (NUTTelA-TAO) observed the field of GRB 250101A at 14:00:32 UT on 2025-01-02, 24.8 hours after the BAT trigger. Observations were made in clear conditions. No source consistent with the XRT (P.A. Evans et al., GCN 38708; T. Komesh et al., GCN 38777) was detected. We report the following results: t-t0(h) UL g' UL r' exposure_time (s) ----------------------------------------- 24.8 21.0 20.8 300 t is the middle time, t0 is the BAT trigger time, t-t0 is given in hours. UL gives the 5 sigma upper limit sensitivity in magnitudes, for images of the given exposure time. Calibration was done with 4 Pan-STARRS catalog stars on our images. No color or other corrections were applied to the values above. ----------------------------------------------- NU = Nazarbayev University, Astana, Kazakhstan UCB = University of California, Berkeley, USA FAI = Fesenkov Astrophysical Institute, Kazakhstan This research has been funded by the Science Committee of the Ministry of Science and Higher Education of the Republic of Kazakhstan (Grant No. AP26103591). The NUTTelA-TAO Team acknowledges the support of the staff of the Assy-Turgen Astrophysical Observatory, Almaty, Kazakhstan, and the Fesenkov Astrophysical Institute, Almaty, Kazkhstan. View this GCN Circular online at https://gcn.nasa.gov/circulars/38790. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36791] IceCube Alert 250102.58: Global MASTER-Net observations report
by GCN Circulars 03 Jan '25

03 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38789 SUBJECT: IceCube Alert 250102.58: Global MASTER-Net observations report DATE: 25/01/03 11:39:39 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-Kislovodsk robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) started inspect of the IceCube Alert 250102.58 (trigger No 61338661,17h 30m 43.68s , +06d 39m 25.2s, R=2.29) errorbox 45219 sec after notice time and 45287 sec after trigger time at 2025-01-03 02:22:49 UT, with upper limit up to 17.6 mag. The observations began at zenith distance = 79 deg. The sun altitude is -24.6 deg. The galactic latitude b = 20 deg., longitude l = 30 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2731505 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 45378 | 2025-01-03 02:22:49 | MASTER-Kislovodsk | (17h 28m 54.07s , +06d 44m 57.4s) | C | 180 | 17.2 | 46794 | 2025-01-03 02:46:26 | MASTER-Kislovodsk | (17h 28m 40.69s , +06d 44m 25.6s) | C | 180 | 17.6 | 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/38789. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36790] EP241231b: optical upper limit with the Liverpool Telescope
by GCN Circulars 03 Jan '25

03 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38788 SUBJECT: EP241231b: optical upper limit with the Liverpool Telescope DATE: 25/01/03 11:30:04 GMT FROM: Amit Kumar at Royal Holloway - UoL/ U of Warwick, UK <amitkundu515(a)gmail.com> A. Kumar, J. R. Maund (RHUL), N. C. Sun (UCAS), W. X. Li, Y. N. Wang (NAOC), and K. Wiersema (Herts) report: We observed the field of Einstein Probe detected EP241231b (Liang et al., GCN 38778) with the IO:O Imager at the 2m Liverpool telescope. We observed a single 200s image in the g-band at 2025-01-02 UT 23:31:26.731 (~2.169 days post-trigger). Further observations were suspended due to bad weather conditions. No new, uncatalogued source was detected in a preliminary visual examination within the EP-WXT localisation uncertainty, down to a limiting g-band magnitude of >21.5 (AB). View this GCN Circular online at https://gcn.nasa.gov/circulars/38788. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36789] GRB 250103A: SVOM detection of a long burst
by GCN Circulars 03 Jan '25

03 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38787 SUBJECT: GRB 250103A: SVOM detection of a long burst DATE: 25/01/03 11:16:17 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> Y. Wang (PMO, CAS), J-X. Cao (GXU), D. Turpin (CEA), S. Guillot (IRAP), H. Goto (CEA), F. Daigne (IAP), L, Zhang (IHEP) report on behalf of the SVOM team: The SVOM/ECLAIRs telescope triggered and located the long duration GRB 250103A (sb25010301) starting at 2025-01-03T09:56:33.551 UTC (Tb). The following trigger information was received on the ground with low-latency by the SVOM VHF Alert Network. The burst was detected by both the on-board Count-Rate Trigger (CRT) and Image Trigger (IMT) and 18 alerts were received. The best detection is obtained by CRT with a signal-to-noise ratio of 18.6 in the 8-50 keV energy band over a time window of 20 s starting at Tb. The localization of the best Alert is RA, Dec = 22.083, -5.096 (J2000). The statistical uncertainty on this position is 4.6 arcminutes, which includes a systematic uncertainty of 2 arcminutes in quadrature. The light curve shows multiple broad peaks in 5-120 keV in ECLAIRs and below 550 keV in GRM with a preliminary T90 duration greater than 250 s (5-120 keV). The SVOM/GRM light curve can be found here: https://www.bursthub.cn//admin/static/svgrb250103A.png SVOM slewed automatically on this burst. MXT began observing the field at 2025-01-03T10:12:28 UTC, 955 seconds after Tb. No X-ray afterglow candidate has been detected in the MXT field of view by the on-board software. Further analysis will be conducted once the X-band telemetry data are received. The Space Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA), French Space Agency (CNES), and the Chinese Academy of Sciences (CAS), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. The SVOM point of contact for this burst is: Yun Wang (wangyun(a)pmo.ac.cn) View this GCN Circular online at https://gcn.nasa.gov/circulars/38787. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36788] GRB 250103A: SVOM detection of a long burst
by GCN Circulars 03 Jan '25

03 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38786 SUBJECT: GRB 250103A: SVOM detection of a long burst DATE: 25/01/03 11:15:16 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> Y. Wang (PMO, CAS), J-X. Cao (GXU), D. Turpin (CEA), S. Guillot (IRAP), H. Goto (CEA), F. Daigne (IAP), L. Zhang (IHEP) report on behalf of the SVOM team: The SVOM/ECLAIRs telescope triggered and located the long duration GRB 250103A (sb25010301) starting at 2025-01-03T09:56:33.551 UTC (Tb). The following trigger information was received on the ground with low-latency by the SVOM VHF Alert Network. The burst was detected by both the on-board Count-Rate Trigger (CRT) and Image Trigger (IMT) and 18 alerts were received. The best detection is obtained by CRT with a signal-to-noise ratio of 18.6 in the 8-50 keV energy band over a time window of 20 s starting at Tb. The localization of the best Alert is RA, Dec = 22.083, -5.096 (J2000). The statistical uncertainty on this position is 4.6 arcminutes, which includes a systematic uncertainty of 2 arcminutes in quadrature. The light curve shows multiple broad peaks in 5-120 keV in ECLAIRs and below 550 keV in GRM with a preliminary T90 duration greater than 250 s (5-120 keV). The SVOM/GRM light curve can be found here: https://www.bursthub.cn//admin/static/svgrb250103A.png SVOM slewed automatically on this burst. MXT began observing the field at 2025-01-03T10:12:28 UTC, 955 seconds after Tb. No X-ray afterglow candidate has been detected in the MXT field of view by the on-board software. Further analysis will be conducted once the X-band telemetry data are received. The Space Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA), French Space Agency (CNES), and the Chinese Academy of Sciences (CAS), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. The SVOM point of contact for this burst is: Yun Wang (wangyun(a)pmo.ac.cn) View this GCN Circular online at https://gcn.nasa.gov/circulars/38786. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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