GCN Circular 45711
Subject
Fermi GRB 260923A: Global MASTER-Net observations report
Event
Date
2026-09-24T00:16:29Z (2 days ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
Via
email
M. Segura, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA)
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)
O.Gress, N.Budnev(ISU)
MASTER-OAFA robotic telescope [1] located in Argentina (OAFA observatory of San Juan National University) started inspect of the Fermi GRB 260923A ( Fermi GBM team, GCN 45710) errorbox 37 sec after notice time and 59 sec after trigger time at 2026-09-23 23:42:36 UT, with upper limit up to 18.6 mag. Observations started at twilight. The observations began at zenith distance = 43 deg. The sun altitude is -15.6 deg.
The galactic latitude b = -57 deg., longitude l = 332 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=3510396
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
65 | 2026-09-23 23:42:36 | MASTER-OAFA | (22h 46m 25.67s , -53d 14m 22.7s) | C | 10 | 16.3 |
85 | 2026-09-23 23:42:36 | MASTER-OAFA | (22h 46m 25.66s , -53d 14m 22.6s) | C | 50 | 17.6 | Coadd
86 | 2026-09-23 23:42:52 | MASTER-OAFA | (22h 46m 25.64s , -53d 14m 21.4s) | C | 20 | 17.1 |
112 | 2026-09-23 23:43:17 | MASTER-OAFA | (22h 46m 25.63s , -53d 14m 20.2s) | C | 20 | 17.8 |
153 | 2026-09-23 23:43:54 | MASTER-OAFA | (22h 53m 16.70s , -53d 46m 50.8s) | C | 30 | 18.1 |
188 | 2026-09-23 23:43:54 | MASTER-OAFA | (22h 53m 16.70s , -53d 46m 50.8s) | C | 100 | 18.3 | Coadd
189 | 2026-09-23 23:44:30 | MASTER-OAFA | (22h 53m 16.68s , -53d 46m 49.0s) | C | 30 | 18.0 |
230 | 2026-09-23 23:45:06 | MASTER-OAFA | (22h 53m 16.69s , -53d 46m 47.0s) | C | 40 | 17.6 |
281 | 2026-09-23 23:45:52 | MASTER-OAFA | (22h 53m 16.67s , -53d 46m 45.4s) | C | 50 | 17.2 |
351 | 2026-09-23 23:45:52 | MASTER-OAFA | (22h 53m 16.67s , -53d 46m 45.4s) | C | 190 | 18.3 | Coadd
342 | 2026-09-23 23:46:48 | MASTER-OAFA | (22h 53m 16.66s , -53d 46m 42.5s) | C | 60 | 17.5 |
418 | 2026-09-23 23:47:54 | MASTER-OAFA | (22h 53m 16.71s , -53d 46m 39.5s) | C | 80 | 18.1 |
509 | 2026-09-23 23:49:20 | MASTER-OAFA | (22h 53m 16.69s , -53d 46m 35.9s) | C | 90 | 18.4 |
1308 | 2026-09-24 00:02:54 | MASTER-OAFA | (23h 04m 22.40s , -54d 00m 27.3s) | C | 60 | 17.9 |
1368 | 2026-09-24 00:02:54 | MASTER-OAFA | (23h 04m 22.39s , -54d 00m 27.3s) | C | 180 | 18.6 | Coadd
1383 | 2026-09-24 00:04:09 | MASTER-OAFA | (23h 04m 16.72s , -54d 01m 03.5s) | C | 60 | 17.8 |
1459 | 2026-09-24 00:05:25 | MASTER-OAFA | (23h 17m 55.73s , -54d 00m 36.9s) | C | 60 | 17.8 |
1534 | 2026-09-24 00:06:40 | MASTER-OAFA | (23h 18m 01.94s , -54d 01m 34.3s) | C | 60 | 17.6 |
1610 | 2026-09-24 00:07:56 | MASTER-OAFA | (23h 04m 18.40s , -54d 01m 52.7s) | C | 60 | 17.7 |
1688 | 2026-09-24 00:09:14 | MASTER-OAFA | (23h 18m 00.49s , -54d 02m 25.2s) | C | 60 | 18.1 |
1766 | 2026-09-24 00:10:31 | MASTER-OAFA | (23h 04m 20.74s , -54d 00m 05.6s) | C | 60 | 17.9 |
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