TITLE: GCN CIRCULAR NUMBER: 41729 SUBJECT: IceCube Alert 250905.84: Global MASTER-Net observations report DATE: 25/09/05 20:39:22 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-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) was pointed to the IceCube Alert 250905.84 (trigger No 25569816,23h 15m 48.96s , +38d 16m 19.2s, R=0.51) errorbox 34 sec after notice time and 87 sec after trigger time at 2025-09-05 20:10:03 UT, with upper limit up to 17.1 mag. The observations began at zenith distance = 80 deg. The sun altitude is -47.4 deg. MASTER-Kislovodsk robotic telescope located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) was pointed to the IceCube Alert 250905.84 errorbox 48 sec after notice time and 101 sec after trigger time at 2025-09-05 20:10:17 UT, with upper limit up to 17.0 mag. The observations began at zenith distance = 15 deg. The sun altitude is -38.6 deg. The galactic latitude b = -21 deg., longitude l = 104 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2985645 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 97 | 2025-09-05 20:10:03 | MASTER-SAAO | (23h 13m 56.30s , +37d 51m 11.7s) | C | 20 | 16.2 | 97 | 2025-09-05 20:10:03 | MASTER-SAAO | (23h 11m 44.72s , +38d 07m 09.5s) | C | 20 | 16.4 | 111 | 2025-09-05 20:10:17 | MASTER-Kislovodsk | (23h 14m 08.98s , +38d 35m 46.0s) | P- | 20 | 15.4 | 136 | 2025-09-05 20:10:17 | MASTER-Kislovodsk | (23h 14m 08.98s , +38d 35m 46.1s) | P- | 70 | 16.2 | Coadd 141 | 2025-09-05 20:10:42 | MASTER-SAAO | (23h 13m 56.43s , +37d 51m 17.0s) | C | 30 | 16.4 | 141 | 2025-09-05 20:10:42 | MASTER-SAAO | (23h 11m 44.83s , +38d 07m 15.6s) | C | 30 | 16.7 | 151 | 2025-09-05 20:10:57 | MASTER-Kislovodsk | (23h 14m 08.82s , +38d 35m 44.8s) | P- | 20 | 15.4 | 195 | 2025-09-05 20:11:31 | MASTER-SAAO | (23h 13m 56.59s , +37d 51m 22.5s) | C | 40 | 16.6 | 195 | 2025-09-05 20:11:31 | MASTER-SAAO | (23h 11m 44.98s , +38d 07m 20.6s) | C | 40 | 16.9 | 196 | 2025-09-05 20:11:37 | MASTER-Kislovodsk | (23h 14m 08.65s , +38d 35m 44.0s) | P- | 30 | 15.8 | 252 | 2025-09-05 20:12:27 | MASTER-Kislovodsk | (23h 14m 08.46s , +38d 35m 43.3s) | P- | 40 | 15.8 | 312 | 2025-09-05 20:12:27 | MASTER-Kislovodsk | (23h 14m 08.45s , +38d 35m 43.5s) | P- | 160 | 16.6 | Coadd 259 | 2025-09-05 20:12:30 | MASTER-SAAO | (23h 13m 56.76s , +37d 51m 27.4s) | C | 50 | 16.7 | 259 | 2025-09-05 20:12:30 | MASTER-SAAO | (23h 11m 45.14s , +38d 07m 24.6s) | C | 50 | 17.0 | 317 | 2025-09-05 20:13:27 | MASTER-Kislovodsk | (23h 14m 08.26s , +38d 35m 43.2s) | P- | 50 | 15.8 | 333 | 2025-09-05 20:13:39 | MASTER-SAAO | (23h 13m 56.93s , +37d 51m 32.0s) | C | 60 | 16.8 | 333 | 2025-09-05 20:13:39 | MASTER-SAAO | (23h 11m 45.32s , +38d 07m 27.8s) | C | 60 | 17.1 | 397 | 2025-09-05 20:14:37 | MASTER-Kislovodsk | (23h 14m 08.05s , +38d 35m 43.6s) | P- | 70 | 16.0 | 412 | 2025-09-05 20:14:58 | MASTER-SAAO | (23h 13m 57.13s , +37d 51m 36.8s) | C | 60 | 16.8 | 412 | 2025-09-05 20:14:58 | MASTER-SAAO | (23h 11m 45.54s , +38d 07m 31.7s) | C | 60 | 17.1 | 497 | 2025-09-05 20:16:07 | MASTER-Kislovodsk | (23h 14m 07.75s , +38d 35m 44.0s) | P- | 90 | 16.2 | 612 | 2025-09-05 20:16:07 | MASTER-Kislovodsk | (23h 14m 07.76s , +38d 35m 44.0s) | P- | 320 | 17.0 | Coadd 617 | 2025-09-05 20:17:58 | MASTER-Kislovodsk | (23h 14m 07.43s , +38d 35m 44.9s) | P- | 110 | 16.4 | 753 | 2025-09-05 20:20:09 | MASTER-Kislovodsk | (23h 14m 07.06s , +38d 35m 46.5s) | P- | 120 | 16.4 | 893 | 2025-09-05 20:22:28 | MASTER-Kislovodsk | (23h 14m 06.67s , +38d 35m 47.7s) | P- | 120 | 16.3 | 1013 | 2025-09-05 20:22:28 | MASTER-Kislovodsk | (23h 14m 06.67s , +38d 35m 47.7s) | P- | 360 | 17.0 | Coadd 1035 | 2025-09-05 20:24:51 | MASTER-Kislovodsk | (23h 14m 06.26s , +38d 35m 49.4s) | P- | 120 | 16.4 | 1175 | 2025-09-05 20:27:11 | MASTER-Kislovodsk | (23h 14m 05.86s , +38d 35m 51.3s) | P- | 120 | 16.4 | 1315 | 2025-09-05 20:29:31 | MASTER-Kislovodsk | (23h 14m 05.49s , +38d 35m 53.3s) | P- | 120 | 16.4 | 1456 | 2025-09-05 20:31:52 | MASTER-Kislovodsk | (23h 14m 05.12s , +38d 35m 55.7s) | P- | 120 | 16.4 | 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/41729. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...