TITLE: GCN CIRCULAR NUMBER: 39481 SUBJECT: Fermi GRB 250226A: Global MASTER-Net observations report DATE: 25/02/26 07:19:05 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, N.Tiurina, P.Balanutsa, , D.Vlasenko, I.Panchenko, A.Kuznetsov, G.Antipov, A.Sankovich, A.Sosnovskij, Yu.Tselik, M.Gulyaev, 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. 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-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) started inspect of the Fermi GRB 250226A ( Fermi GBM team, GCN 39479) errorbox 24 sec after notice time and 42 sec after trigger time at 2025-02-26 06:35:39 UT, with upper limit up to 20.6 mag. The observations began at zenith distance = 68 deg. The sun altitude is -42.6 deg. The galactic latitude b = 63 deg., longitude l = 32 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2792277 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 47 | 2025-02-26 06:35:39 | MASTER-OAFA | (14h 37m 17.00s , +28d 44m 10.7s) | C | 10 | 17.3 | 62 | 2025-02-26 06:35:39 | MASTER-OAFA | (14h 37m 17.01s , +28d 44m 10.7s) | C | 40 | 18.0 | Coadd 48 | 2025-02-26 06:35:40 | MASTER-OAFA | (14h 47m 34.56s , +29d 06m 42.6s) | C | 10 | 18.8 | 73 | 2025-02-26 06:35:40 | MASTER-OAFA | (14h 47m 34.57s , +29d 06m 42.7s) | C | 60 | 19.9 | Coadd 133 | 2025-02-26 06:35:40 | MASTER-OAFA | (14h 47m 34.56s , +29d 06m 42.7s) | C | 180 | 20.5 | Coadd 97 | 2025-02-26 06:36:24 | MASTER-OAFA | (14h 37m 16.85s , +28d 44m 13.0s) | C | 20 | 17.7 | 98 | 2025-02-26 06:36:25 | MASTER-OAFA | (14h 47m 34.39s , +29d 06m 43.3s) | C | 20 | 19.2 | 132 | 2025-02-26 06:37:04 | MASTER-OAFA | (14h 37m 16.73s , +28d 44m 14.3s) | C | 10 | 17.3 | 143 | 2025-02-26 06:37:04 | MASTER-OAFA | (14h 47m 34.22s , +29d 06m 43.3s) | C | 30 | 19.5 | 168 | 2025-02-26 06:37:40 | MASTER-OAFA | (14h 37m 16.62s , +28d 44m 15.1s) | C | 10 | 17.2 | 193 | 2025-02-26 06:37:40 | MASTER-OAFA | (14h 37m 16.64s , +28d 44m 15.1s) | C | 60 | 18.5 | Coadd 178 | 2025-02-26 06:37:40 | MASTER-OAFA | (14h 47m 34.11s , +29d 06m 43.3s) | C | 30 | 19.6 | 223 | 2025-02-26 06:37:40 | MASTER-OAFA | (14h 47m 34.28s , +29d 06m 43.1s) | C | 120 | 20.0 | Coadd 209 | 2025-02-26 06:38:16 | MASTER-OAFA | (14h 37m 16.46s , +28d 44m 15.8s) | C | 20 | 17.8 | 219 | 2025-02-26 06:38:16 | MASTER-OAFA | (14h 47m 33.97s , +29d 06m 42.9s) | C | 40 | 19.7 | 260 | 2025-02-26 06:39:02 | MASTER-OAFA | (14h 37m 16.25s , +28d 44m 16.5s) | C | 30 | 18.0 | 270 | 2025-02-26 06:39:02 | MASTER-OAFA | (14h 47m 33.77s , +29d 06m 42.4s) | C | 50 | 19.9 | 321 | 2025-02-26 06:39:58 | MASTER-OAFA | (14h 37m 15.96s , +28d 44m 16.6s) | C | 40 | 18.3 | 331 | 2025-02-26 06:39:58 | MASTER-OAFA | (14h 47m 33.52s , +29d 06m 41.8s) | C | 60 | 19.9 | 439 | 2025-02-26 06:41:46 | MASTER-OAFA | (14h 38m 47.22s , +23d 27m 51.0s) | C | 60 | 18.4 | 529 | 2025-02-26 06:41:46 | MASTER-OAFA | (14h 38m 47.22s , +23d 27m 51.0s) | C | 240 | 19.5 | Coadd 449 | 2025-02-26 06:41:46 | MASTER-OAFA | (14h 48m 37.68s , +23d 50m 29.6s) | C | 80 | 20.2 | 559 | 2025-02-26 06:41:46 | MASTER-OAFA | (14h 48m 37.68s , +23d 50m 29.7s) | C | 300 | 20.6 | Coadd 535 | 2025-02-26 06:43:12 | MASTER-OAFA | (14h 38m 46.84s , +23d 27m 50.2s) | C | 80 | 18.6 | 545 | 2025-02-26 06:43:12 | MASTER-OAFA | (14h 48m 37.34s , +23d 50m 28.1s) | C | 100 | 20.2 | 652 | 2025-02-26 06:44:59 | MASTER-OAFA | (14h 38m 46.33s , +23d 27m 48.1s) | C | 100 | 18.8 | 662 | 2025-02-26 06:44:59 | MASTER-OAFA | (14h 48m 36.92s , +23d 50m 26.1s) | C | 120 | 20.2 | 793 | 2025-02-26 06:47:04 | MASTER-OAFA | (14h 38m 45.75s , +23d 27m 45.8s) | C | 130 | 18.7 | 953 | 2025-02-26 06:47:04 | MASTER-OAFA | (14h 38m 45.75s , +23d 27m 45.8s) | C | 450 | 19.7 | Coadd 803 | 2025-02-26 06:47:05 | MASTER-OAFA | (14h 48m 36.39s , +23d 50m 23.4s) | C | 150 | 20.2 | 973 | 2025-02-26 06:49:50 | MASTER-OAFA | (14h 38m 45.03s , +23d 27m 41.9s) | C | 160 | 18.8 | 983 | 2025-02-26 06:49:50 | MASTER-OAFA | (14h 49m 41.16s , +23d 48m 31.7s) | C | 180 | 20.2 | 1163 | 2025-02-26 06:49:50 | MASTER-OAFA | (14h 49m 41.16s , +23d 48m 31.8s) | C | 540 | 20.6 | Coadd 1167 | 2025-02-26 06:53:04 | MASTER-OAFA | (14h 38m 44.30s , +23d 27m 37.0s) | C | 160 | 18.7 | 1177 | 2025-02-26 06:53:04 | MASTER-OAFA | (14h 49m 40.51s , +23d 48m 27.3s) | C | 180 | 20.1 | 1362 | 2025-02-26 06:56:19 | MASTER-OAFA | (14h 38m 43.40s , +23d 27m 31.4s) | C | 160 | 18.6 | 1372 | 2025-02-26 06:56:19 | MASTER-OAFA | (14h 49m 39.69s , +23d 48m 22.0s) | C | 180 | 20.1 | 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/39481. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...