TITLE: GCN CIRCULAR NUMBER: 42381 SUBJECT: LAT GRB251022.94: Global MASTER-Net observations report DATE: 25/10/23 03:11:21 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs lipunov@xray.sai.msu.ru
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 (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) was pointed to the LAT GRB251022.94 (trigger No 782865260,04h 21m 31.18s , -19d 18m 35.6s, R=0.32) errorbox 13 sec after notice time and 16215 sec after trigger time at 2025-10-23 03:04:30 UT, with upper limit up to 17.2 mag. Observations started at twilight. The observations began at zenith distance = 32 deg. The sun altitude is -10.1 deg.
The galactic latitude b = -41 deg., longitude l = 216 deg.
Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3021522
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________
16245 | 2025-10-23 03:04:30 | MASTER-SAAO | (04h 21m 02.62s , -19d 31m 07.4s) | C | 60 | 17.2 | 16245 | 2025-10-23 03:04:30 | MASTER-SAAO | (04h 19m 05.26s , -19d 15m 42.2s) | P\ | 60 | 16.7 | 16324 | 2025-10-23 03:05:49 | MASTER-SAAO | (04h 21m 02.39s , -19d 31m 03.5s) | C | 60 | 16.7 | 16324 | 2025-10-23 03:05:49 | MASTER-SAAO | (04h 19m 05.05s , -19d 15m 37.8s) | P\ | 60 | 16.6 | 16404 | 2025-10-23 03:07:08 | MASTER-SAAO | (04h 19m 04.85s , -19d 15m 33.5s) | P\ | 60 | 16.6 | Filter C is a clear (unfiltred) band.
The observation and reduction will continue. The message may be cited.
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