TITLE: GCN CIRCULAR NUMBER: 39431 SUBJECT: Fermi trigger No 762020305: Global MASTER-Net observations report DATE: 25/02/23 16:46:54 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-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 GRB250223.68 (trigger No 762020305,17h 30m 28.80s , +41d 02m 24.0s, R=5.1) errorbox 569 sec after notice time and 603 sec after trigger time at 2025-02-23 16:28:23 UT, with upper limit up to 16.6 mag. The observations began at zenith distance = 74 deg. The sun altitude is -47.4 deg. The galactic latitude b = 32 deg., longitude l = 66 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2788242 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 632 | 2025-02-23 16:28:23 | MASTER-Tunka | (17h 31m 26.47s , +40d 50m 52.7s) | C | 55 | 15.9 | 687 | 2025-02-23 16:28:23 | MASTER-Tunka | (17h 31m 26.50s , +40d 50m 52.7s) | C | 165 | 16.5 | Coadd 691 | 2025-02-23 16:29:22 | MASTER-Tunka | (17h 31m 26.58s , +40d 50m 54.0s) | C | 55 | 16.1 | 749 | 2025-02-23 16:30:21 | MASTER-Tunka | (17h 31m 26.76s , +40d 50m 55.4s) | C | 55 | 16.6 | 810 | 2025-02-23 16:31:19 | MASTER-Tunka | (17h 31m 27.02s , +40d 50m 55.5s) | C | 60 | 14.9 | 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/39431. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...