TITLE: GCN CIRCULAR NUMBER: 40454 SUBJECT: Fermi GRB 250512A: Global MASTER-Net observations report DATE: 25/05/13 16:16:08 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-Tunka robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Applied Physics Institute, Irkutsk State University) started inspect of the Fermi GRB 250512A ( Fermi GBM team, GCN 40436) errorbox 1 days 10178 sec after notice time and 1 days 10229 sec after trigger time at 2025-05-13 14:52:05 UT, with upper limit up to 17.9 mag. Observations started at twilight. The observations began at zenith distance = 38 deg. The sun altitude is -14.8 deg. The galactic latitude b = 19 deg., longitude l = 112 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2868622 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 96660 | 2025-05-13 14:52:05 | MASTER-Tunka | (17h 57m 54.62s , +86d 24m 49.3s) | C | 60 | 14.5 | 96798 | 2025-05-13 14:54:24 | MASTER-Tunka | (20h 39m 40.13s , +76d 43m 27.8s) | C | 60 | 13.0 | 96962 | 2025-05-13 14:57:08 | MASTER-Tunka | (21h 30m 19.84s , +78d 37m 25.1s) | C | 60 | 13.4 | 100410 | 2025-05-13 15:54:36 | MASTER-Tunka | (18h 00m 35.78s , +86d 29m 00.2s) | C | 60 | 17.8 | 100410 | 2025-05-13 15:54:36 | MASTER- | (17h 52m 00.08s , +86d 24m 46.8s) | C | 60 | 17.5 | 100489 | 2025-05-13 15:55:55 | MASTER-Tunka | (20h 40m 09.79s , +76d 45m 49.8s) | C | 60 | 17.9 | 100489 | 2025-05-13 15:55:55 | MASTER- | (20h 37m 45.37s , +76d 40m 53.1s) | C | 60 | 17.4 | 100690 | 2025-05-13 15:59:16 | MASTER-Tunka | (21h 31m 11.48s , +78d 36m 43.9s) | C | 60 | 17.7 | 100871 | 2025-05-13 16:02:17 | MASTER-Tunka | (21h 47m 34.81s , +76d 42m 05.1s) | C | 60 | 17.1 | 100871 | 2025-05-13 16:02:17 | MASTER- | (21h 45m 01.87s , +76d 37m 00.9s) | C | 60 | 16.4 | Coadd 101045 | 2025-05-13 16:05:11 | MASTER-Tunka | (18h 00m 13.68s , +86d 28m 34.8s) | C | 60 | 17.0 | 101129 | 2025-05-13 16:06:35 | MASTER-Tunka | (20h 40m 08.00s , +76d 47m 07.4s) | C | 60 | 16.6 | 101209 | 2025-05-13 16:07:54 | MASTER-Tunka | (21h 02m 16.63s , +74d 50m 57.9s) | C | 60 | 17.0 | 101287 | 2025-05-13 16:09:13 | MASTER-Tunka | (21h 31m 11.49s , +78d 36m 46.3s) | C | 60 | 17.4 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. View this GCN Circular online at https://gcn.nasa.gov/circulars/40454. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...