GRB 251113A
GCN Circular 42689
Subject
GRB 251113A: Glowbug gamma-ray detection
Date
2025-11-14T22:40:15Z (6 months 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 251113A, which was also detected by Fermi/GBM (GCN 42671, 42672) and AstroSat/CZTI (GCN 42688).
Using an adaptive window with a resolution of 32-ms, the burst onset is determined to be 2025-11-13 17:37:28.512 with a duration of 24.6 s and a total significance of about 82 sigma. The light curve comprises three primary peaks at ~T0+8s, +12s, and +18s. Low-level emission may be present up to ~T0+37s. Note that data from ~T0+22s to T0+26s 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 42688
Subject
GRB 251113A: AstroSat CZTI detection
Date
2025-11-14T21:27:07Z (6 months ago)
From
Anuraag Arya at IIT Bombay <aryaanuraag910@gmail.com>
Via
Web form
A. Goyal (IITB), A. Arya (IITB), S. Salunke (IUCAA), M. Tembhurnikar (IUCAA), Harsha K. H. (IUCAA), 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 251113A which was also detected by Fermi GBM (Fermi GBM Team, GCN Circ. 42671).
The source was clearly detected in the CZT detectors in the 20-200 keV energy range. The light curve peaks at 2025-11-13 17:37:42.84 UTC. The measured peak count rate associated with the burst is 208 (+40, -21) counts/s above the background in the combined data of all quadrants, with a total of 2657 (+431, -393) counts. The local mean background count rate was 269 (+4, -5) counts/s. Using cumulative rates, we measure a T90 of 23 (+2, -5) 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 2025-11-13 17:37:42.35 UTC. The measured peak count rate associated with the burst is 350 (+68, -53) counts/s above the background in the combined data of all quadrants, with a total of 4325 (+900, -914) counts. The local mean background count rate was 1169 (+11, -11) counts/s. We measure a T90 of 22 (+2, -4) 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
GCN Circular 42673
Subject
Fermi GRB 251113A: Global MASTER-Net observations report
Date
2025-11-13T18:46:05Z (6 months 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-SAAO robotic telescope [1] located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB 251113A ( Fermi GBM team, GCN 42671) errorbox 3189 sec after notice time and 3223 sec after trigger time at 2025-11-13 18:31:13 UT, with upper limit up to 18.9 mag. Observations started at twilight. The observations began at zenith distance = 73 deg. The sun altitude is -15.3 deg.
The galactic latitude b = -35 deg., longitude l = 179 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=3041542
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
3254 | 2025-11-13 18:31:13 | MASTER-SAAO | (03h 38m 31.68s , +07d 50m 32.6s) | C | 60 | 18.0 |
3314 | 2025-11-13 18:31:13 | MASTER-SAAO | (03h 38m 31.68s , +07d 50m 32.6s) | C | 180 | 18.8 | Coadd
3254 | 2025-11-13 18:31:13 | MASTER-SAAO | (03h 36m 49.82s , +08d 06m 25.7s) | C | 60 | 17.6 |
3345 | 2025-11-13 18:32:45 | MASTER-SAAO | (03h 38m 31.92s , +07d 48m 57.6s) | C | 60 | 18.2 |
3345 | 2025-11-13 18:32:45 | MASTER-SAAO | (03h 36m 50.05s , +08d 04m 49.4s) | C | 60 | 17.7 |
3438 | 2025-11-13 18:34:17 | MASTER-SAAO | (03h 38m 35.46s , +07d 50m 09.7s) | C | 60 | 18.2 |
3438 | 2025-11-13 18:34:18 | MASTER-SAAO | (03h 36m 53.59s , +08d 06m 00.6s) | C | 60 | 17.8 |
3560 | 2025-11-13 18:35:50 | MASTER-SAAO | (03h 38m 30.08s , +07d 49m 40.0s) | C | 120 | 18.8 |
3560 | 2025-11-13 18:35:50 | MASTER-SAAO | (03h 36m 48.15s , +08d 05m 30.5s) | C | 120 | 18.2 |
3713 | 2025-11-13 18:38:23 | MASTER-SAAO | (03h 38m 29.14s , +07d 50m 41.1s) | C | 120 | 18.9 |
3713 | 2025-11-13 18:38:23 | MASTER-SAAO | (03h 36m 47.11s , +08d 06m 30.9s) | C | 120 | 18.5 |
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 42672
Subject
GRB 251113A: BALROG localization (Fermi Trigger 784748255 / GRB 251113734)
Date
2025-11-13T18:19:45Z (6 months ago)
From
Jochen Greiner at MPE <jcgrog@mpe.mpg.de>
Via
email
T. Preis (University of Innsbruck) & J. Greiner (MPE Garching) report:
The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger
784748255 at 17:37:30 on 13 Nov. 2025 were automatically fitted for spectrum
and sky location with BALROG (Burgess et al. 2018, MNRAS 476, 1427;
Berlato et al. 2019, ApJ 873, 60).
The best-fit position is:
RA(2000.0) = 52.6 deg
Decl.(2000.0) = 10.4 deg
The 1 sigma statistical error radius is 1.6 deg.
We estimate an additional systematic error of 1 deg.
Further details are available at:
https://grb.mpe.mpg.de/grb/GRB251113734/
The Healpix map can be downloaded from:
https://grb.mpe.mpg.de/grb/GRB251113734/healpix
The location parameters are available as JSON at:
https://grb.mpe.mpg.de/grb/GRB251113734/json
GCN Circular 42671
Subject
GRB 251113A: Fermi GBM Final Real-time Localization
Date
2025-11-13T17:48:06Z (6 months 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 17:37:30 UT on 13 Nov 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 251113A (trigger 784748255.384296 / 251113734).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 55.1, Dec = 8.2 (J2000 degrees, equivalent to J2000 03h 40m, 8d 11'), with a statistical uncertainty of 1.5 degrees.
The angle from the Fermi LAT boresight is 52.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251113734/quicklook/glg_skymap_all_bn251113734.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/bn251113734/quicklook/glg_healpix_all_bn251113734.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251113734/quicklook/glg_lc_medres34_bn251113734.gif