TITLE: GCN CIRCULAR NUMBER: 44715 SUBJECT: Fermi trigger No 801580882: Global MASTER-Net observations report DATE: 26/05/27 23:32:27 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), M. Segura, 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-Kislovodsk robotic telescope [1] located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) started inspect of the Fermi GRB260527.56 (trigger No 801580882,04h 33m 31.92s , +25d 09m 00.0s, R=34.02) errorbox 32285 sec after notice time and 32319 sec after trigger time at 2026-05-27 22:19:57 UT, with upper limit up to 16.2 mag. The observations began at zenith distance = 79 deg. The sun altitude is -22.7 deg. MASTER-Tavrida robotic telescope located in Russia (Lomonosov MSU, SAI Crimea astronomical station) started inspect of the Fermi GRB260527.56 errorbox 35876 sec after notice time and 35911 sec after trigger time at 2026-05-27 23:19:48 UT, with upper limit up to 14.4 mag. The observations began at zenith distance = 79 deg. The sun altitude is -20.1 deg. The galactic latitude b = -15 deg., longitude l = 174 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3342387 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 32350 | 2026-05-27 22:19:57 | MASTER-Kislovodsk | (02h 18m 21.64s , +48d 14m 30.3s) | C | 60 | 15.8 | 32548 | 2026-05-27 22:23:15 | MASTER-Kislovodsk | (02h 42m 51.73s , +50d 08m 35.3s) | C | 60 | 15.6 | 32648 | 2026-05-27 22:24:55 | MASTER-Kislovodsk | (02h 13m 21.39s , +46d 22m 36.9s) | C | 60 | 14.4 | 32856 | 2026-05-27 22:28:22 | MASTER-Kislovodsk | (02h 36m 35.69s , +48d 14m 11.1s) | C | 60 | 15.2 | 33178 | 2026-05-27 22:33:44 | MASTER-Kislovodsk | (02h 08m 47.36s , +44d 29m 27.5s) | C | 60 | 14.9 | 33494 | 2026-05-27 22:39:01 | MASTER-Kislovodsk | (02h 30m 48.83s , +46d 22m 41.4s) | C | 60 | 15.0 | 33817 | 2026-05-27 22:44:24 | MASTER-Kislovodsk | (02h 04m 47.76s , +42d 34m 55.9s) | C | 60 | 14.8 | 34202 | 2026-05-27 22:50:49 | MASTER-Kislovodsk | (02h 25m 46.25s , +44d 28m 34.2s) | C | 60 | 13.9 | 34313 | 2026-05-27 22:52:40 | MASTER-Kislovodsk | (02h 54m 41.12s , +48d 16m 38.9s) | C | 60 | 14.7 | 34422 | 2026-05-27 22:54:29 | MASTER-Kislovodsk | (02h 00m 58.83s , +40d 43m 24.4s) | C | 60 | 14.8 | 34722 | 2026-05-27 22:59:28 | MASTER-Kislovodsk | (02h 48m 29.20s , +46d 22m 19.9s) | C | 60 | 14.9 | 34843 | 2026-05-27 23:01:30 | MASTER-Kislovodsk | (02h 21m 06.32s , +42d 36m 37.1s) | C | 60 | 15.3 | 34940 | 2026-05-27 23:03:07 | MASTER-Kislovodsk | (01h 57m 39.49s , +38d 48m 17.6s) | C | 60 | 15.3 | 35715 | 2026-05-27 23:16:02 | MASTER-Kislovodsk | (02h 16m 57.39s , +40d 42m 08.4s) | C | 60 | 16.2 | 35941 | 2026-05-27 23:19:48 | MASTER-Tavrida | (03h 04m 17.85s , +49d 18m 29.0s) | C | 60 | 14.4 | 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/44715. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...