2026-09-29T07:24:06.543Z | rev 0
Xing-Hao Luo, Chen-Wei Wang, Ren-Yang Zhao, Shao-Lin Xiong (IHEP) report on behalf of GECAM team:
GECAM-B was triggered in-flight by GRB 260926A, at 2026-09-26T16:20:15.550 UTC (denoted as T0), which is also detected by Fermi/GBM (Fermi GBM team, GCN #45761).
According to the GECAM-B light curves in about 70-6000 keV, this burst mainly consists of multiple pulses with a duration (T90) of 8.5 +1.5/-2 s.
The GECAM-B light curve can be found here:
https://www.bursthub.cn//gcn/2026/gecambgrb260926A.png
Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) mission originally consists of two micro-satellites (GECAM-A and GECAM-B) launched in Dec. 2020. As the third member of GECAM constellation, GECAM-C was launched onboard SATech-01 experimental satellite in July 2022. GECAM mission is funded by the Chinese Academy of Sciences (CAS).
GCN 45777: GRB 260926A: Glowbug gamma-ray detection
2026-09-29T02:03:47.872Z | rev 0
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 260926A, which was also detected by Fermi/GBM (GCN 45761).
Using an adaptive window with a resolution of 32-ms, the burst onset is determined to be 2026-09-26 16:20:12.064 with a duration of 5.1 s and a total significance of about 18.9 sigma. The light curve comprises a single peak.
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.
[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 45763: Fermi GRB 260926A: Global MASTER-Net observations report
2026-09-26T17:31:32.636Z | rev 0
O.Gress, N.Budnev(ISU)
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 (Lomonosov MSU)
D.Buckley (SAAO),
A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity)
A.Sosnovskij (Lomonosov MSU)
A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory)
L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez,
A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory)
R.Rebolo (The Instituto de Astrofisica de Canarias)
M. Segura, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA)
MASTER-Tunka robotic telescope [1] located in Russia (Applied Physics Institute, Irkutsk State University) started inspect of the Fermi GRB 260926A ( Fermi GBM team, GCN 45761) errorbox 94 sec after notice time and 126 sec after trigger time at 2026-09-26 16:22:21 UT, with upper limit up to 18.5 mag. The observations began at zenith distance = 23 deg. The sun altitude is -38.9 deg.
The galactic latitude b = 3 deg., longitude l = 126 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=3512177
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
137 | 2026-09-26 16:22:21 | MASTER-Tunka | (01h 52m 49.46s , +67d 56m 33.0s) | C | 20 | 18.0 |
157 | 2026-09-26 16:22:21 | MASTER-Tunka | (01h 52m 49.45s , +67d 56m 33.0s) | C | 60 | 18.5 | Coadd
137 | 2026-09-26 16:22:21 | MASTER-Tunka | (01h 54m 13.21s , +67d 47m 48.4s) | C | 20 | 18.1 |
160 | 2026-09-26 16:22:44 | MASTER-Tunka | (01h 52m 49.35s , +67d 56m 32.1s) | C | 20 | 17.9 |
160 | 2026-09-26 16:22:44 | MASTER-Tunka | (01h 54m 13.11s , +67d 47m 47.7s) | C | 20 | 18.1 |
184 | 2026-09-26 16:23:08 | MASTER-Tunka | (01h 52m 49.24s , +67d 56m 31.4s) | C | 20 | 17.8 |
184 | 2026-09-26 16:23:08 | MASTER-Tunka | (01h 54m 12.99s , +67d 47m 47.0s) | C | 20 | 17.9 |
205 | 2026-09-26 16:23:32 | MASTER-Tunka | (01h 52m 49.12s , +67d 56m 30.8s) | C | 15 | 17.6 |
220 | 2026-09-26 16:23:32 | MASTER-Tunka | (01h 52m 49.11s , +67d 56m 30.8s) | C | 45 | 18.2 | Coadd
205 | 2026-09-26 16:23:32 | MASTER-Tunka | (01h 54m 12.91s , +67d 47m 46.5s) | C | 15 | 17.7 |
220 | 2026-09-26 16:23:32 | MASTER-Tunka | (01h 54m 12.91s , +67d 47m 46.4s) | C | 45 | 18.2 | Coadd
224 | 2026-09-26 16:23:50 | MASTER-Tunka | (01h 52m 49.04s , +67d 56m 30.2s) | C | 15 | 17.5 |
224 | 2026-09-26 16:23:50 | MASTER-Tunka | (01h 54m 12.82s , +67d 47m 46.1s) | C | 15 | 17.7 |
242 | 2026-09-26 16:24:09 | MASTER-Tunka | (01h 52m 48.94s , +67d 56m 29.5s) | C | 15 | 17.6 |
243 | 2026-09-26 16:24:09 | MASTER-Tunka | (01h 54m 12.75s , +67d 47m 45.5s) | C | 15 | 17.6 |
261 | 2026-09-26 16:24:27 | MASTER-Tunka | (01h 52m 48.85s , +67d 56m 29.0s) | C | 15 | 17.6 |
276 | 2026-09-26 16:24:27 | MASTER-Tunka | (01h 52m 48.84s , +67d 56m 29.0s) | C | 45 | 18.2 | Coadd
261 | 2026-09-26 16:24:27 | MASTER-Tunka | (01h 54m 12.68s , +67d 47m 45.2s) | C | 15 | 17.6 |
276 | 2026-09-26 16:24:27 | MASTER-Tunka | (01h 54m 12.68s , +67d 47m 45.1s) | C | 45 | 18.3 | Coadd
279 | 2026-09-26 16:24:46 | MASTER-Tunka | (01h 52m 48.75s , +67d 56m 28.5s) | C | 15 | 17.6 |
280 | 2026-09-26 16:24:46 | MASTER-Tunka | (01h 54m 12.60s , +67d 47m 44.8s) | C | 15 | 17.7 |
298 | 2026-09-26 16:25:04 | MASTER-Tunka | (01h 52m 48.66s , +67d 56m 27.9s) | C | 15 | 17.6 |
298 | 2026-09-26 16:25:04 | MASTER-Tunka | (01h 54m 12.54s , +67d 47m 44.3s) | C | 15 | 17.8 |
316 | 2026-09-26 16:25:23 | MASTER-Tunka | (01h 52m 48.58s , +67d 56m 27.3s) | C | 15 | 17.7 |
317 | 2026-09-26 16:25:23 | MASTER-Tunka | (01h 54m 12.49s , +67d 47m 43.9s) | C | 15 | 17.8 |
594 | 2026-09-26 16:30:01 | MASTER-Tunka | (01h 17m 01.24s , +65d 03m 25.5s) | C | 15 | 17.4 |
609 | 2026-09-26 16:30:01 | MASTER-Tunka | (01h 17m 01.23s , +65d 03m 25.5s) | C | 45 | 17.9 | Coadd
594 | 2026-09-26 16:30:01 | MASTER-Tunka | (01h 18m 17.43s , +64d 54m 28.1s) | C | 15 | 17.5 |
609 | 2026-09-26 16:30:01 | MASTER-Tunka | (01h 18m 17.43s , +64d 54m 28.1s) | C | 45 | 18.0 | Coadd
613 | 2026-09-26 16:30:19 | MASTER-Tunka | (01h 17m 01.17s , +65d 03m 24.3s) | C | 15 | 17.2 |
613 | 2026-09-26 16:30:19 | MASTER-Tunka | (01h 18m 17.34s , +64d 54m 27.5s) | C | 15 | 17.3 |
632 | 2026-09-26 16:30:38 | MASTER-Tunka | (01h 17m 01.10s , +65d 03m 23.7s) | C | 15 | 17.2 |
632 | 2026-09-26 16:30:38 | MASTER-Tunka | (01h 18m 17.26s , +64d 54m 26.9s) | C | 15 | 17.3 |
647 | 2026-09-26 16:30:56 | MASTER-Tunka | (01h 17m 01.03s , +65d 03m 23.0s) | C | 10 | 17.1 |
647 | 2026-09-26 16:30:56 | MASTER-Tunka | (01h 18m 17.21s , +64d 54m 26.3s) | C | 10 | 17.2 |
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 45761: GRB 260926A: Fermi GBM Final Real-time Localization
2026-09-26T16:30:40.231Z | rev 0
The Fermi GBM team reports the detection of a likely LONG GRB
At 16:20:14 UT on 26 Sep 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260926A (trigger 812132419.655086 / 260926681).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 20.2, Dec = 65.3 (J2000 degrees, equivalent to J2000 01h 20m, 65d 17'), with a statistical uncertainty of 5.8 degrees.
The angle from the Fermi LAT boresight is 81.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260926681/quicklook/glg_skymap_all_bn260926681.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260926681/quicklook/glg_healpix_all_bn260926681.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260926681/quicklook/glg_lc_medres34_bn260926681.gif