TITLE: GCN CIRCULAR NUMBER: 44479 SUBJECT: IceCube Alert 260505A: Global MASTER-Net observations report DATE: 26/05/05 22:26:33 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-Kislovodsk robotic telescope [1] located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) was pointed to the IceCube Alert 260505A (trigger No 58544625,16h 27m 57.60s , +54d 52m 12.0s, R=0.67) errorbox 1 days 3353 sec after notice time and 1 days 3411 sec after trigger time at 2026-05-05 22:08:12 UT, with upper limit up to 19.2 mag. The observations began at zenith distance = 13 deg. The sun altitude is -29.0 deg. The galactic latitude b = 42 deg., longitude l = 84 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3293437 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 89842 | 2026-05-05 22:08:12 | MASTER-Kislovodsk | (16h 26m 24.62s , +55d 13m 07.6s) | C | 60 | 13.2 | 89842 | 2026-05-05 22:08:12 | MASTER-Kislovodsk | (16h 26m 52.94s , +54d 49m 59.4s) | C | 60 | 19.1 | 89940 | 2026-05-05 22:09:50 | MASTER-Kislovodsk | (16h 26m 58.23s , +54d 48m 57.5s) | C | 60 | 19.1 | 90036 | 2026-05-05 22:11:26 | MASTER-Kislovodsk | (16h 26m 12.84s , +55d 11m 17.5s) | C | 60 | 13.3 | 90037 | 2026-05-05 22:11:27 | MASTER-Kislovodsk | (16h 26m 52.47s , +54d 47m 56.7s) | C | 60 | 19.1 | 90125 | 2026-05-05 22:12:56 | MASTER-Kislovodsk | (16h 26m 24.80s , +55d 12m 02.6s) | C | 60 | 13.6 | 90125 | 2026-05-05 22:12:56 | MASTER-Kislovodsk | (16h 26m 56.65s , +54d 48m 13.7s) | C | 60 | 19.2 | 90215 | 2026-05-05 22:14:25 | MASTER-Kislovodsk | (16h 26m 17.07s , +55d 12m 10.3s) | C | 60 | 12.9 | 90215 | 2026-05-05 22:14:25 | MASTER-Kislovodsk | (16h 26m 52.12s , +54d 49m 38.8s) | C | 60 | 19.2 | 90303 | 2026-05-05 22:15:54 | MASTER-Kislovodsk | (16h 26m 16.58s , +55d 10m 30.3s) | C | 60 | 13.1 | 90303 | 2026-05-05 22:15:54 | MASTER-Kislovodsk | (16h 26m 51.53s , +54d 48m 00.8s) | C | 60 | 19.1 | 90391 | 2026-05-05 22:17:21 | MASTER-Kislovodsk | (16h 26m 20.13s , +55d 12m 14.8s) | C | 60 | 12.7 | 90391 | 2026-05-05 22:17:21 | MASTER-Kislovodsk | (16h 26m 54.99s , +54d 49m 43.2s) | C | 60 | 19.0 | 90479 | 2026-05-05 22:18:50 | MASTER-Kislovodsk | (16h 26m 12.86s , +55d 11m 27.4s) | C | 60 | 12.7 | 90479 | 2026-05-05 22:18:50 | MASTER-Kislovodsk | (16h 26m 47.70s , +54d 48m 56.2s) | C | 60 | 19.2 | 90568 | 2026-05-05 22:20:18 | MASTER-Kislovodsk | (16h 26m 47.19s , +54d 49m 56.1s) | C | 60 | 19.2 | 90656 | 2026-05-05 22:21:46 | MASTER-Kislovodsk | (16h 26m 19.15s , +55d 11m 26.0s) | C | 60 | 12.7 | 90656 | 2026-05-05 22:21:46 | MASTER-Kislovodsk | (16h 26m 53.95s , +54d 48m 57.0s) | C | 60 | 19.2 | 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/44479. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...