TITLE: GCN CIRCULAR NUMBER: 40803 SUBJECT: Fermi GRB 250621A: Global MASTER-Net observations report DATE: 25/06/21 02:30:51 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-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 250621A ( Fermi GBM team, GCN 40801) errorbox 79 sec after notice time and 111 sec after trigger time at 2025-06-21 01:16:46 UT, with upper limit up to 18.2 mag. The observations began at zenith distance = 77 deg. The sun altitude is -45.4 deg.
The galactic latitude b = 10 deg., longitude l = 248 deg.
Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2910652
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________
122 | 2025-06-21 01:16:46 | MASTER-OAFA | (08h 35m 57.13s , -26d 43m 55.5s) | C | 20 | 17.4 | 161 | 2025-06-21 01:17:21 | MASTER-OAFA | (08h 46m 34.40s , -23d 40m 16.6s) | C | 30 | 17.8 | 202 | 2025-06-21 01:17:57 | MASTER-OAFA | (08h 46m 34.42s , -23d 40m 16.3s) | C | 40 | 17.9 | 253 | 2025-06-21 01:18:43 | MASTER-OAFA | (08h 46m 34.45s , -23d 40m 16.4s) | C | 50 | 18.0 | 315 | 2025-06-21 01:19:40 | MASTER-OAFA | (08h 46m 34.42s , -23d 40m 15.2s) | C | 60 | 17.9 | 386 | 2025-06-21 01:20:46 | MASTER-OAFA | (08h 46m 34.44s , -23d 40m 15.4s) | C | 70 | 18.2 | 472 | 2025-06-21 01:22:02 | MASTER-OAFA | (08h 46m 34.52s , -23d 40m 15.8s) | C | 90 | 18.2 | 573 | 2025-06-21 01:23:38 | MASTER-OAFA | (08h 46m 34.55s , -23d 40m 15.7s) | C | 100 | 18.2 | 702 | 2025-06-21 01:25:32 | MASTER-OAFA | (08h 39m 15.15s , -24d 49m 47.5s) | C | 130 | 18.1 | 848 | 2025-06-21 01:27:48 | MASTER-OAFA | (08h 39m 15.35s , -24d 49m 48.3s) | C | 150 | 17.9 | 1019 | 2025-06-21 01:30:24 | MASTER-OAFA | (08h 39m 15.58s , -24d 49m 49.7s) | C | 180 | 17.8 | 1205 | 2025-06-21 01:33:30 | MASTER-OAFA | (08h 39m 15.88s , -24d 49m 51.5s) | C | 180 | 17.6 | 1392 | 2025-06-21 01:36:36 | MASTER-OAFA | (08h 39m 16.16s , -24d 49m 53.1s) | C | 180 | 17.5 | 1578 | 2025-06-21 01:39:42 | MASTER-OAFA | (08h 39m 16.38s , -24d 49m 59.7s) | C | 180 | 17.2 | 1763 | 2025-06-21 01:42:48 | MASTER-OAFA | (08h 39m 16.61s , -24d 50m 07.5s) | C | 180 | 16.8 | Filter C is a clear (unfiltred) band.
The observation and reduction will continue. The message may be cited.
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