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[vsnet-grb-info 40964] GRB 251128A: SVOM/GRM observation of a long burst
by GCN Circulars 29 Nov '25

29 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42894 SUBJECT: GRB 251128A: SVOM/GRM observation of a long burst DATE: 25/11/29 14:47:25 GMT FROM: zhangjinpeng(a)ihep.ac.cn SVOM/GRM team: Jin-Peng Zhang, Chen-Wei Wang, Shi-Jie Zheng, Yue Huang, Shao-Lin Xiong, Shuang-Nan Zhang (IHEP) SVOM/ECLAIRs team: Jean-Luc Atteia (IRAP) Report on behalf of the SVOM team: SVOM/GRM on-ground search was triggered by GRB 251128A at 2025-11-28T04:22:24.000 (T0), which is also detected by Fermi/GBM (Fermi GBM Team, GCN #42865). The GRM light curve shows that this burst consists of multiple pulses with a T90 of 47 +8/-5 s in the 15-5000 keV band. The SVOM/GRM light curve can be found here: https://www.bursthub.cn//admin/static/svgrb251128A.png In addition, the position of this burst, as determined by Fermi/GBM (RA=117.5, Dec = 52.2, GCN #42865), is located at about 139.4 degrees from the SVOM optical axis, which is out of the ECLAIRs field of view. With this localization, the time-averaged spectrum from T0-10 to T0+45 s is best fit by a power law function. The power law index is -2.36 +0.22/-0.28. The event fluence (10-1000 keV) in this time interval is (3.08 +0.34/-0.35)E-05 erg/cm^2. 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: Jin-Peng Zhang (IHEP) (zhangjinpeng(a)ihep.ac.cn) View this GCN Circular online at https://gcn.nasa.gov/circulars/42894. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40963] GRB 251128A: Insight-HXMT/HE detection
by GCN Circulars 29 Nov '25

29 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42893 SUBJECT: GRB 251128A: Insight-HXMT/HE detection DATE: 25/11/29 14:43:15 GMT FROM: zhangjinpeng(a)ihep.ac.cn Jin-Peng Zhang, Chen-Wei Wang, Chao Zheng, and Shao-Lin Xiong (IHEP) report on behalf of the Insight-HXMT team: At 2025-11-28T04:22:22.000 (T0), Insight-HXMT/HE detected a long GRB 251128A, which is also detected by Fermi/GBM (Fermi GBM Team, GCN #42865). The Insight-HXMT/HE light curve mainly consists of multiple pulses with a T90 of 44 +11/-18 s. The 1s peak rate, measured from T0+9.5 s, is 604 cnts/sec. Insight-HXMT/HE detected a total of 3694 counts from this burst. The Insight-HXMT/HE light curve can be found here: https://www.bursthub.cn//admin/static/hxmtgrb251128A.png All measurements above are made with the CsI detectors of Insight-HXMT/HE operating in the regular mode with the energy range of about 60-900 keV (deposited energy). Only gamma-rays with energy greater than about 200 keV can penetrate the spacecraft and leave signals in the CsI detectors installed inside of the telescope. Insight-HXMT is the first Chinese space X-ray telescope, which was funded jointly by the China National Space Administration (CNSA) and the Chinese Academy of Sciences (CAS). More information about it could be found at: http://www.hxmt.org View this GCN Circular online at https://gcn.nasa.gov/circulars/42893. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40962] SVOM GRB 251129A : MASTER optical counterpart detection
by GCN Circulars 29 Nov '25

29 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42892 SUBJECT: SVOM GRB 251129A : MASTER optical counterpart detection DATE: 25/11/29 14:26:34 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V.M. Lipunov, A.Kuznetsov, I.Panchenko, E.Gorbovskoy, G.Antipov, P.Balanutsa, V.Senik, N. Tiurina, K.Zhirkov, Ya.Kechin, A.Chasovnikov, D.Vlasenko, Yu. Tselik(Lomonosov MSU, SAI, Moscow), O.A.Gress, N.M.Budnev, O.Ershova (Irkutsk State University), R. Podesta, C.Francile, F. Podesta, E. Gonzalez (OAFA, San Juan Uni.,Argentina); D. Buckley (SAAO, South Africa), A. Sosnovskij (CrAO RAS), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino, J.Martinez, A.R.Corella,L.H.Rodriguez (INAOE, Guillermo Haro Astrophysic Observatory, Mexico) V.M.Pillet, R.Rebolo Lopez (The Instituto de Astrofisica de Canarias,Spain), MASTER-Kislovodsk robotic telescope (Global MASTER-Net [1-4], http://observ.pereplet.ru) started inspect (Lipunov et al. GCN 42878) of SVOM GRB 251129A ( GCN 42877) 9 sec after notice time (997 sec after trigger time) at 2025-11-29 02:48:01 UT There is optical counterpart with unfiltered m_OT=18.7(auto-detection) at 2025-11-25 02:48:01UT, that was discovered by SVOM/COLIBRÍ (Angulo et al. GCN 42880) at 2025-11-29 02:51:22UT and also observed by SVOM/VT (Wu et al. GCN 42882, Li et al. GCN 42887), VT (Maxi et al. GCN 42885). Real time updated cover map and OT position are available here: https://master.sai.msu.ru/site/master2/observ.php?id=3054567 [1] Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L [2] Lipunov et al. 2022, Universe, Vol. 8(5), id.271 [3] Lipunov et a. 2019, ARep, vol.63, 293 [4] Lipunov V., Kornilov V., Gorbovskoy E., Tiurina N., Kuznetsov A. 2023, Astronomical Robotic Networks and Operative Multichanel Astrophysics,Lomonosov MSU PRESS, 591pp. http://www.pereplet.ru/lipunov/625.html#625 View this GCN Circular online at https://gcn.nasa.gov/circulars/42892. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40961] GRB 251129A: Swift-XRT afterglow detection
by GCN Circulars 29 Nov '25

29 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42891 SUBJECT: GRB 251129A: Swift-XRT afterglow detection DATE: 25/11/29 12:29:18 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> K.L. Page (U. Leicester), V. D'Elia (SSDC & INAF-OAR), B. Sbarufatti (INAF-OAB), J.A. Kennea (PSU), D.N. Burrows (PSU), S. Lanava (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 SVOM/ECLAIRs-detected burst GRB 251129A. We searched for X-ray sources in 732 s of Photon Counting (PC) mode data. The total exposure at the position of the afterglow (see below) is 2.3 ks, obtained between T0+16.5 ks and T0+28.5 ks. An uncatalogued X-ray source is detected within the estimated 3-sigma SVOM/ECLAIRs error region (49 arcsec) and is above the RASS 3-sigma upper limit at this position, and is therefore likely the GRB afterglow. Using 2336 s of PC mode data and 4 UVOT images, we find an enhanced XRT position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 224.33074, +79.29312 which is equivalent to: RA (J2000): 14h 57m 19.38s Dec(J2000): +79d 17' 35.2" with an uncertainty of 2.1 arcsec (radius, 90% confidence). This position is 26 arcsec from the SVOM/ECLAIRs position. The position is consistent with the optical afterglow (GCNs 42880, 42882, 42883, 42885, 42887) and the EP X-ray transient (GCN 42884). The light curve can be modelled can be modelled with a power-law decay with a decay index of alpha=6.23 (+0.32, -0.29). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.71 (+0.22, -0.20). The best-fitting absorption column is 7.3 (+3.7, -3.3) x 10^20 cm^-2, in excess of the Galactic value of 2.9 x 10^20 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 2.6 x 10^-11 (3.7 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 7.3 (+3.7, -3.3) x 10^20 cm^-2 Galactic foreground: 2.9 x 10^20 cm^-2 Excess significance: 2.2 sigma Photon index: 2.71 (+0.22, -0.20) If the light curve continues to decay with a power-law decay index of 6.2, the count rate at T+24 hours will be 1.1 x 10^-4 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.0 x 10^-15 (4.2 x 10^-15) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at https://www.swift.ac.uk/xrt_products/00021892. The results of the full analysis of the XRT observations are available at https://www.swift.ac.uk/ToO_GRBs/00021892. This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/42891. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40960] The EP-WXT trigger 01709248941 is triggered by the known source Perseus Cluster
by GCN Circulars 29 Nov '25

29 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42890 SUBJECT: The EP-WXT trigger 01709248941 is triggered by the known source Perseus Cluster DATE: 25/11/29 11:57:01 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> T. Wu, H. C. Ding (AHNU), Y. Wu, Y. H. Jiang, C. Y. Dai (NJU), Y. Wang (PMO), W. J. Zhang, Y. Liu (NAO, CAS), on behalf of the Einstein Probe (EP) team: The EP-WXT trigger 01709248941 at 2025-11-29T11:07:16 is associated with the known source Perseus Cluster. 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/42890. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40959] Swift trigger 1418333 is not an astrophysical source
by GCN Circulars 29 Nov '25

29 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42889 SUBJECT: Swift trigger 1418333 is not an astrophysical source DATE: 25/11/29 11:24:27 GMT FROM: K.L. Page at U Leicester <klp5(a)leicester.ac.uk> R. Gupta (NASA GSFC), N. P. M. Kuin (UCL-MSSL), K. L. Page (U Leicester) and T. M. Parsotan (GSFC) report on behalf of the Neil Gehrels Swift Observatory Team: Trigger 1418333 was caused by particles in the South Atlantic Anomaly, and is not an interesting, astrophysical event. View this GCN Circular online at https://gcn.nasa.gov/circulars/42889. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40958] GRB 251129A: Swift ToO observations
by GCN Circulars 29 Nov '25

29 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42888 SUBJECT: GRB 251129A: Swift ToO observations DATE: 25/11/29 07:05:48 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-detected event GRB 251129A. Automated analysis of the XRT data will be presented online at https://www.swift.ac.uk/ToO_GRBs/00021892 Any uncatalogued X-ray sources detected in this analysis will be reported on this website and via GCN COUNTERPART notices. These are not necessarily related to the SVOM/ECLAIRs event. 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/42888. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40957] GRB 251129A: SVOM/VT optical fading
by GCN Circulars 29 Nov '25

29 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42887 SUBJECT: GRB 251129A: SVOM/VT optical fading DATE: 25/11/29 05:41:54 GMT FROM: Huali Li at at NAOC, SVOM <lhl(a)nao.cas.cn> H. L. Li , L. P. Xin, Y. L. Qiu, C. Wu, Z. H. Yao, Y. N. Ma, X. H. Han, J. Wang, Y. Xu, P. P. Zhang, W. J. Xie, Y. J. Xiao, H. B. Cai, J. R. Xu, J. S. Deng, J. Y. Wei (NAOC), J. Palmerio (CEA), W. J. Tan (IHEP), D. F. Kong (GXU) report on behalf of the SVOM/VT team. SVOM/VT performed an automatic slew to the field of GRB 251129A (sb25112901, Tan et al., GCN 42879). The observation stared at 2025-11-29T02:43:03 UTC, I.e., 658 seconds post trigger in the VT_B (400nm-650nm) and VT_R (650nm-1000nm) channels simultaneously. With the downloaded early X band data, the optical counterpart (Angulo et al. GCN 42880; Watson, GCN 42883; Wu et al., GCN 42882; Masi et al. GCN 42885) was clearly detected in both channels. The measurements are given below: Mid_time Band Exposure Time Magnitude (AB) 12.43 min VT_B 50 sec 18.16+/-0.03 mag 12.43 min VT_R 50 sec 17.89+/-0.03 mag 44.96 min VT_B 50 sec 19.11+/-0.04 mag 44.96 min VT_R 50 sec 18.80+/-0.03 mag It was fading with a slope of about 0.7 with a single power law. Our photometry was not corrected for Galactic extinction. 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/42887. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40956] EP251129a: Global MASTER-Net observations report
by GCN Circulars 29 Nov '25

29 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42886 SUBJECT: EP251129a: Global MASTER-Net observations report DATE: 25/11/29 05:36:20 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-Kislovodsk robotic telescope [1] located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) was pointed to the EP251129a ( EP Team et al., GCN 42884) errorbox 107 sec after trigger time at 2025-11-29 03:16:10 UT, with upper limit up to 17.6 mag. Observations started at twilight. The observations began at zenith distance = 44 deg. The sun altitude is -11.4 deg. The galactic latitude b = 36 deg., longitude l = 116 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3054702 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 167 | 2025-11-29 03:16:10 | MASTER-Kislovodsk | (14h 59m 24.03s , +79d 38m 56.6s) | C | 120 | 17.2 | 287 | 2025-11-29 03:16:10 | MASTER-Kislovodsk | (14h 59m 24.03s , +79d 38m 56.6s) | C | 360 | 17.6 | Coadd 167 | 2025-11-29 03:16:10 | MASTER-Kislovodsk | (15h 21m 34.38s , +79d 11m 04.2s) | C | 120 | 17.4 | 307 | 2025-11-29 03:18:30 | MASTER-Kislovodsk | (14h 59m 22.72s , +79d 39m 05.4s) | C | 120 | 17.0 | 307 | 2025-11-29 03:18:30 | MASTER-Kislovodsk | (15h 21m 33.89s , +79d 11m 14.4s) | C | 120 | 17.1 | 447 | 2025-11-29 03:20:49 | MASTER-Kislovodsk | (14h 59m 21.42s , +79d 39m 14.1s) | C | 120 | 16.6 | 447 | 2025-11-29 03:20:49 | MASTER-Kislovodsk | (15h 21m 32.90s , +79d 11m 24.4s) | C | 120 | 16.7 | 587 | 2025-11-29 03:23:09 | MASTER-Kislovodsk | (14h 59m 20.23s , +79d 39m 22.9s) | C | 120 | 16.4 | 707 | 2025-11-29 03:23:09 | MASTER-Kislovodsk | (14h 59m 20.29s , +79d 39m 22.8s) | C | 360 | 17.0 | Coadd 587 | 2025-11-29 03:23:09 | MASTER-Kislovodsk | (15h 21m 29.63s , +79d 11m 35.4s) | C | 120 | 14.6 | 727 | 2025-11-29 03:25:29 | MASTER-Kislovodsk | (14h 59m 19.13s , +79d 39m 30.8s) | C | 120 | 16.3 | 867 | 2025-11-29 03:27:49 | MASTER-Kislovodsk | (14h 59m 17.67s , +79d 39m 36.8s) | C | 120 | 16.1 | 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/42886. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40955] GRB 251129A: Optical Observations via Virtual Telescope Project, Italy
by GCN Circulars 29 Nov '25

29 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42885 SUBJECT: GRB 251129A: Optical Observations via Virtual Telescope Project, Italy DATE: 25/11/29 05:27:43 GMT FROM: Gianluca Masi at Virtual Telescope Project <gianluca(a)bellatrixobservatory.org> Gianluca Masi, Virtual Telescope Project (Italy), reports: We attempted to observe the optical counterpart of GRB 251129A (Wenjun et al., GCN 42877) with the 14” robotic unit available at the Virtual Telescope Project facility in Manciano, Italy, equipped with a KAF-3200E based CCD camera, its QE peaking (90%) in the red part of the spectrum. We collected five, 300-second unfiltered exposures, then we averaged them. The central time of the resulting stack was 29 Nov., 04:54:23 UTC, that is about 2.4 hours after the burst. We detected a bright object at the following position (J2000.0): R.A.: 14 57 18.81 Decl.: +79 17 34.6 mean residuals < 0.1” on both axes R= 19.5 (assuming R-mags from Gaia DR2 for the reference stars). This position is consistent with Angulo et al. (GCN 42880). The source is not present in the PanSTARRS DR1 dataset. View this GCN Circular online at https://gcn.nasa.gov/circulars/42885. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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