GRB 251127A
GCN Circular 42911
Subject
GRB 251127A: SVOM/GRM observation
Date
2025-12-01T02:08:58Z (2 days ago)
From
Chenwei Wang at IHEP <cwwang@ihep.ac.cn>
Via
Web form
SVOM/GRM team: Chen-Wei Wang, Zheng-Hang Yu, Yue Huang, Shi-Jie Zheng, Shao-Lin Xiong, Shuang-Nan Zhang (IHEP)
SVOM/ECLAIRs team: Jean-Luc Atteia (IRAP)
Report on behalf of the SVOM team:
SVOM/GRM was triggered in-flight by a burst GRB 251127A at 2025-11-27T03:17:44.000 UTC (T0), which is also detected by Fermi/GBM (Fermi GBM team, GCN #42852) and Glowbug (C.C. Cheung et al., GCN #42872).
With the event-by-event data downloaded through the X-band ground station, the GRM light curve shows that this burst consists of mutiple peaks with a T90 of 17.5 +4.0/-2.5 s in the 15-5000 keV band.
The SVOM/GRM light curve can be found here:
https://www.bursthub.cn//admin/static/svgrb251127A.png
In addition, the position of this burst, as determined by Fermi/GBM (RA= 155.6, DEC= 30.2, GCN#42852), is located at about 46 degrees from the SVOM optical axis, which is outside the ECLAIRs field of view.
With this localization, the time-averaged spectrum from T0-2 to T0+18 s is best fitted by a power law function with an exponential high-energy cutoff. The power law index is -1.09 +0.22/-0.21 and the cutoff energy, parameterized as Epeak, is 267 +251/-77 keV. The event fluence (10-1000 keV) in this time interval is (1.05 +0.11/-0.11)E-05 erg/cm^2.
The 1s peak spectrum, measured from T0-1 to T0 s, if fitted by a power law function with an exponential high-energy cutoff, the power law index is -1.01 +0.18/-0.16 and the cutoff energy, parameterized as Epeak, is 591 +503/-197 keV. The flux (10-1000 keV) in this time interval is (7.84 +0.88/-1.01)E-07 erg/cm^2/s.
The localization of GRB 251127A in the 'Amati' relation diagram is shown at:
https://www.bursthub.cn//admin/static/svgrb251127A_amati.png
The localization of GRB 251127A in the 'Yonetoku' relation diagram is shown at:
https://www.bursthub.cn//admin/static/svgrb251127A_yonetoku.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: Chen-Wei Wang (IHEP)(cwwang@ihep.ac.cn)
GCN Circular 42872
Subject
GRB 251127A: Glowbug gamma-ray detection
Date
2025-11-28T14:57:16Z (4 days ago)
From
C.C. Cheung at Naval Research Lab <Teddy.Cheung@nrl.navy.mil>
Via
Web form
C.C. Cheung, R. Woolf, M. Kerr, J.E. Grove (NRL), A. Goldstein (USRA), C.A. Wilson-Hodge, D. Kocevski (MSFC), and M.S. Briggs (UAH) report:
The Glowbug gamma-ray telescope [1,2,3], operating on the International Space Station, reports the detection of GRB 251127A, which was also detected by Fermi/GBM (GCN 42852).
Using an adaptive window with a resolution of 32-ms, the burst onset is determined to be 2025-11-27 03:17:42.528 with a duration of 14.8 s and a total significance of about 16.1 sigma. The light curve comprises a bright peak at ~T0 followed by a fainter multi-peaked structure. Note that data from ~T0+7s to +11s suffered from deadtime in various detectors.
The analysis results presented here are preliminary and use a response function that lacks a detailed characterization of the surrounding passive structure of the ISS.
Glowbug is a NASA-funded technology demonstrator for sensitive, low-cost gamma-ray transient telescopes developed, built, and operated by the U.S. Naval Research Laboratory (NRL) with support from the University of Alabama in Huntsville, USRA, and NASA MSFC. It was launched on 2023 March 15 aboard the Department of Defense Space Test Program’s STP-H9 to the ISS and operated until 2024 April when it was put in safe storage on orbit. Glowbug was removed from storage and resumed operation on 2025 September 12.
[1] Grove, J.E. et al. 2020, Proc. Yamada Conf. LXXI, arXiv:2009.11959
[2] Woolf, R.S. et al. 2022, Proc. SPIE, 12181, id. 121811O
[3] Woolf, R.S. et al. 2024, Proc. SPIE, 13151, id. 1315108
Distribution Statement A: Approved for public release. Distribution is unlimited.
GCN Circular 42853
Subject
Fermi GRB 251127A: Global MASTER-Net observations report
Date
2025-11-27T03:30:35Z (6 days ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
Via
email
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) started inspect of the Fermi GRB 251127A ( Fermi GBM team, GCN 42852) errorbox 26 sec after notice time and 61 sec after trigger time at 2025-11-27 03:18:44 UT, with upper limit up to 16.6 mag. Observations started at twilight. The observations began at zenith distance = 14 deg. The sun altitude is -10.6 deg.
The galactic latitude b = 58 deg., longitude l = 199 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=3052815
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
67 | 2025-11-27 03:18:44 | MASTER-Kislovodsk | (10h 26m 49.07s , +29d 21m 07.8s) | C | 10 | 15.7 |
67 | 2025-11-27 03:18:44 | MASTER-Kislovodsk | (10h 21m 41.55s , +29d 42m 18.9s) | C | 10 | 14.2 |
96 | 2025-11-27 03:19:13 | MASTER-Kislovodsk | (10h 26m 49.14s , +29d 21m 07.1s) | C | 10 | 15.7 |
96 | 2025-11-27 03:19:14 | MASTER-Kislovodsk | (10h 21m 41.27s , +29d 42m 13.3s) | C | 10 | 14.1 |
144 | 2025-11-27 03:19:52 | MASTER-Kislovodsk | (10h 28m 11.83s , +32d 30m 38.8s) | C | 30 | 16.6 |
144 | 2025-11-27 03:19:52 | MASTER-Kislovodsk | (10h 22m 52.53s , +32d 52m 02.7s) | C | 30 | 15.4 |
194 | 2025-11-27 03:20:42 | MASTER-Kislovodsk | (10h 22m 52.49s , +32d 52m 02.0s) | C | 30 | 15.2 |
194 | 2025-11-27 03:20:42 | MASTER-Kislovodsk | (10h 28m 11.82s , +32d 30m 38.3s) | C | 30 | 16.4 |
249 | 2025-11-27 03:21:31 | MASTER-Kislovodsk | (10h 22m 52.28s , +32d 51m 59.6s) | C | 40 | 15.4 |
249 | 2025-11-27 03:21:31 | MASTER-Kislovodsk | (10h 28m 11.77s , +32d 30m 37.9s) | C | 40 | 16.6 |
314 | 2025-11-27 03:22:31 | MASTER-Kislovodsk | (10h 28m 11.71s , +32d 30m 37.2s) | C | 50 | 16.4 |
314 | 2025-11-27 03:22:31 | MASTER-Kislovodsk | (10h 22m 52.22s , +32d 51m 59.0s) | C | 50 | 15.1 |
394 | 2025-11-27 03:23:41 | MASTER-Kislovodsk | (10h 22m 51.99s , +32d 51m 57.2s) | C | 70 | 15.1 |
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
GCN Circular 42852
Subject
GRB 251127A: Fermi GBM Final Real-time Localization
Date
2025-11-27T03:28:10Z (6 days ago)
From
Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>
Via
email
The Fermi GBM team reports the detection of a likely LONG GRB
At 03:17:42 UT on 27 Nov 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 251127A (trigger 785906267.770746 / 251127137).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 155.6, Dec = 30.2 (J2000 degrees, equivalent to J2000 10h 22m, 30d 11'), with a statistical uncertainty of 4.1 degrees.
The angle from the Fermi LAT boresight is 24.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251127137/quicklook/glg_skymap_all_bn251127137.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251127137/quicklook/glg_healpix_all_bn251127137.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251127137/quicklook/glg_lc_medres34_bn251127137.gif