TITLE: GCN CIRCULAR NUMBER: 43219 SUBJECT: EP251222a: Global MASTER-Net observations report DATE: 25/12/23 15:36:29 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 [1] located in Russia (Applied Physics Institute, Irkutsk State University) was pointed to the EP251222a ( EP Team et al., GCN 43200) errorbox 25213 sec after notice time and 69548 sec after trigger time at 2025-12-23 10:37:14 UT, with upper limit up to 16.4 mag. Observations started at twilight. The observations began at zenith distance = 78 deg. The sun altitude is -13.8 deg. MASTER-Kislovodsk robotic telescope located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) was pointed to the EP251222a errorbox 39747 sec after notice time and 84082 sec after trigger time at 2025-12-23 14:39:28 UT, with upper limit up to 16.9 mag. Observations started at twilight. The observations began at zenith distance = 75 deg. The sun altitude is -10.5 deg. The galactic latitude b = -35 deg., longitude l = 194 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3081644 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 66002 | 2025-12-23 09:36:37 | MASTER- | (04h 15m 01.67s , -00d 43m 08.5s) | C | 180 | 16.3 | 69578 | 2025-12-23 10:37:14 | MASTER-Tunka | (04h 09m 44.57s , -01d 55m 17.1s) | C | 60 | 16.4 | 69578 | 2025-12-23 10:37:14 | MASTER-Tunka | (04h 09m 58.83s , -02d 01m 41.0s) | C | 60 | 16.1 | 69649 | 2025-12-23 10:38:24 | MASTER-Tunka | (04h 09m 58.86s , -02d 01m 41.4s) | C | 60 | 15.7 | 69649 | 2025-12-23 10:38:25 | MASTER-Tunka | (04h 09m 44.41s , -01d 55m 16.5s) | C | 60 | 16.1 | 84112 | 2025-12-23 14:39:28 | MASTER-Kislovodsk | (04h 07m 57.86s , -01d 42m 13.8s) | C | 60 | 16.9 | 84112 | 2025-12-23 14:39:28 | MASTER-Kislovodsk | (04h 07m 58.58s , -01d 19m 40.7s) | C | 60 | 15.8 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. [1] - V.M. Lipunov, V.G. Kornilov, E.S. Gorbovskoy, N.A. Tiurina & A.S.Kuznetsov, 2023, Astronomical Robotic Networks and Operative Multichanel Astrophysics, Lomonosov MSU PRESS, 591pp. http : // www.pereplet.ru/lipunov/625.html View this GCN Circular online at https://gcn.nasa.gov/circulars/43219. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...