GRB 251102A
GCN Circular 42542
Subject
GRB 251102A: AstroSat CZTI detection
Date
2025-11-03T09:34:19Z (a day ago)
From
Anuraag Arya at IIT Bombay <aryaanuraag910@gmail.com>
Via
Web form
M. Tembhurnikar (IUCAA), S. Salunke (IUCAA), Harsha K. H. (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 251102A which was also detected by Fermi GBM (Fermi GBM Team, GCN Circ. 42531) and Konus-Wind (IPN notices) .
The source was clearly detected in the CZT detectors in the 20-200 keV energy range. The light curve peaks at 2025-11-02 02:04:02.50 UTC. The measured peak count rate associated with the burst is 138 (+36, -15) counts/s above the background in the combined data of all quadrants, with a total of 1258 (+189, -199) counts. The local mean background count rate was 275 (+3, -4) counts/s. Using cumulative rates, we measure a T90 of 16.2 (+1.0, -0.9) 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 2025-11-02 02:03:58.03 UTC. The measured peak count rate associated with the burst is 164 (+71, -18) counts/s above the background in the combined data of all quadrants, with a total of 1518 (+313, -350) counts. The local mean background count rate was 1256 (+5, -5) counts/s. We measure a T90 of 17.0 (+1.7, -2.0) 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 42532
Subject
Fermi GRB 251102A: Global MASTER-Net observations report
Date
2025-11-02T02:30:56Z (3 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 (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 251102A ( Fermi GBM team, GCN 42531) errorbox 28 sec after notice time and 63 sec after trigger time at 2025-11-02 02:04:49 UT, with upper limit up to 16.9 mag. The observations began at zenith distance = 47 deg. The sun altitude is -18.9 deg.
MASTER-Tavrida robotic telescope located in Russia (Lomonosov MSU, SAI Crimea astronomical station) started inspect of the Fermi GRB 251102A errorbox 99 sec after notice time and 133 sec after trigger time at 2025-11-02 02:05:59 UT, with upper limit up to 18.5 mag. The observations began at zenith distance = 52 deg. The sun altitude is -24.5 deg.
The galactic latitude b = 54 deg., longitude l = 122 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=3030148
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
68 | 2025-11-02 02:04:49 | MASTER-Kislovodsk | (12h 52m 47.94s , +64d 29m 27.5s) | C | 10 | 15.1 |
69 | 2025-11-02 02:04:49 | MASTER-Kislovodsk | (13h 12m 42.94s , +64d 05m 30.2s) | C | 10 | 15.2 |
109 | 2025-11-02 02:05:29 | MASTER-Kislovodsk | (12h 52m 48.10s , +64d 29m 29.8s) | C | 10 | 15.0 |
115 | 2025-11-02 02:05:36 | MASTER-Kislovodsk | (13h 12m 42.91s , +64d 05m 32.1s) | C | 10 | 15.3 |
149 | 2025-11-02 02:05:59 | MASTER-Tavrida | (13h 10m 49.26s , +63d 40m 20.7s) | C | 30 | 16.0 |
150 | 2025-11-02 02:06:05 | MASTER-Kislovodsk | (12h 52m 48.12s , +64d 29m 32.0s) | C | 20 | 15.3 |
150 | 2025-11-02 02:06:05 | MASTER-Kislovodsk | (13h 12m 42.97s , +64d 05m 34.4s) | C | 20 | 15.6 |
199 | 2025-11-02 02:06:44 | MASTER-Tavrida | (13h 02m 23.04s , +63d 53m 59.4s) | C | 40 | 17.3 |
254 | 2025-11-02 02:06:44 | MASTER-Tavrida | (13h 02m 23.04s , +63d 53m 59.3s) | C | 150 | 18.4 | Coadd
195 | 2025-11-02 02:06:45 | MASTER-Kislovodsk | (12h 52m 48.13s , +64d 29m 35.6s) | C | 30 | 16.2 |
195 | 2025-11-02 02:06:45 | MASTER-Kislovodsk | (13h 12m 43.03s , +64d 05m 37.7s) | C | 30 | 16.3 |
249 | 2025-11-02 02:07:35 | MASTER-Kislovodsk | (12h 52m 48.13s , +64d 29m 39.1s) | C | 40 | 16.1 |
249 | 2025-11-02 02:07:35 | MASTER-Kislovodsk | (13h 12m 43.06s , +64d 05m 41.4s) | C | 40 | 16.2 |
255 | 2025-11-02 02:07:35 | MASTER-Tavrida | (13h 02m 22.99s , +63d 53m 58.1s) | C | 50 | 17.3 |
314 | 2025-11-02 02:08:30 | MASTER-Tavrida | (13h 02m 22.85s , +63d 53m 57.1s) | C | 60 | 17.5 |
314 | 2025-11-02 02:08:35 | MASTER-Kislovodsk | (12h 52m 48.15s , +64d 29m 42.9s) | C | 50 | 16.1 |
314 | 2025-11-02 02:08:35 | MASTER-Kislovodsk | (13h 12m 43.10s , +64d 05m 45.4s) | C | 50 | 16.6 |
394 | 2025-11-02 02:09:45 | MASTER-Kislovodsk | (12h 52m 48.21s , +64d 29m 47.4s) | C | 70 | 16.4 |
394 | 2025-11-02 02:09:45 | MASTER-Kislovodsk | (13h 12m 43.08s , +64d 05m 49.9s) | C | 70 | 16.9 |
398 | 2025-11-02 02:09:49 | MASTER-Tavrida | (13h 02m 22.62s , +63d 53m 55.9s) | C | 70 | 17.5 |
473 | 2025-11-02 02:09:49 | MASTER-Tavrida | (13h 02m 22.60s , +63d 53m 55.8s) | C | 220 | 18.5 | Coadd
502 | 2025-11-02 02:11:23 | MASTER-Tavrida | (13h 02m 22.27s , +63d 53m 54.9s) | C | 90 | 18.1 |
616 | 2025-11-02 02:13:07 | MASTER-Tavrida | (12h 53m 48.03s , +64d 07m 08.3s) | C | 110 | 17.9 |
624 | 2025-11-02 02:13:15 | MASTER-Kislovodsk | (12h 43m 41.31s , +63d 58m 15.7s) | C | 110 | 16.5 |
624 | 2025-11-02 02:13:15 | MASTER-Kislovodsk | (13h 03m 03.27s , +63d 33m 47.8s) | C | 110 | 16.8 |
759 | 2025-11-02 02:15:25 | MASTER-Kislovodsk | (12h 43m 41.35s , +63d 58m 20.8s) | C | 120 | 15.2 |
874 | 2025-11-02 02:17:49 | MASTER-Tavrida | (12h 37m 03.34s , +63d 40m 00.7s) | C | 60 | 16.4 |
943 | 2025-11-02 02:18:59 | MASTER-Tavrida | (13h 02m 20.04s , +63d 55m 18.8s) | C | 60 | 16.6 |
1012 | 2025-11-02 02:20:07 | MASTER-Tavrida | (13h 02m 14.69s , +63d 55m 45.5s) | C | 60 | 16.9 |
1102 | 2025-11-02 02:20:07 | MASTER-Tavrida | (13h 02m 14.66s , +63d 55m 45.5s) | C | 240 | 17.9 | Coadd
1080 | 2025-11-02 02:21:16 | MASTER-Tavrida | (13h 02m 13.43s , +63d 53m 45.0s) | C | 60 | 17.0 |
1178 | 2025-11-02 02:22:24 | MASTER-Tavrida | (13h 02m 16.73s , +63d 55m 29.1s) | C | 120 | 16.6 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
GCN Circular 42531
Subject
GRB 251102A: Fermi GBM Final Real-time Localization
Date
2025-11-02T02:14:07Z (3 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 02:03:46 UT on 2 Nov 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 251102A (trigger 783741831.07104 / 251102086).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 193.5, Dec = 63.9 (J2000 degrees, equivalent to J2000 12h 54m, 63d 53'), with a statistical uncertainty of 2.2 degrees.
The angle from the Fermi LAT boresight is 58.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251102086/quicklook/glg_skymap_all_bn251102086.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/bn251102086/quicklook/glg_healpix_all_bn251102086.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251102086/quicklook/glg_lc_medres34_bn251102086.gif