TITLE: GCN CIRCULAR NUMBER: 35621 SUBJECT: IceCube Alert 240123.48: Global MASTER-Net observations report DATE: 24/01/24 17:13:28 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru> V. Lipunov, V.Kornilov, E. Gorbovskoy, K. Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, V.Senik, D. Vlasenko, G.Antipov, D.Zimnukhov, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D. Cheryasov, Ya.Kechin, Yu.Tselik, A. Sosnovskij (Lomonosov Moscow State University, SAI, Physics Department), R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA), R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias), D. Buckley (South African Astronomical Observatory), O.A. Gress, N.M. Budnev, O.Ershova (Irkutsk State University, API), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), V. Yurkov, A. Gabovich (Blagoveschensk Educational State University) 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 240123.48 (trigger No 34080563,23h 50m 33.12s , +04d 22m 12.0s, R=0.51) errorbox 26249 sec after notice time and 26305 sec after trigger time at 2024-01-23 18:44:01 UT, with upper limit up to 16.8 mag. Observations started at twilight. The observations began at zenith distance = 71 deg. The sun altitude is -11.7 deg. MASTER-Kislovodsk robotic telescope located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) was pointed to the IceCube Alert 240123.48 errorbox 1 days 19825 sec after notice time and 1 days 19881 sec after trigger time at 2024-01-24 16:56:57 UT, with upper limit up to 17.5 mag. The observations began at zenith distance = 65 deg. The sun altitude is -30.1 deg. The galactic latitude b = -55 deg., longitude l = 97 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2363232 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 26336 | 2024-01-23 18:44:01 | MASTER-SAAO | (23h 57m 38.77s , +04d 59m 29.0s) | C | 60 | 16.2 | 26336 | 2024-01-23 18:44:01 | MASTER-SAAO | (23h 59m 26.43s , +04d 46m 52.8s) | C | 60 | 16.3 | 27297 | 2024-01-23 19:00:02 | MASTER-SAAO | (23h 59m 37.22s , +04d 49m 10.8s) | C | 60 | 16.8 | 106312 | 2024-01-24 16:56:57 | MASTER-Kislovodsk | (23h 56m 37.15s , +05d 21m 39.6s) | C | 60 | 17.5 | 106393 | 2024-01-24 16:58:18 | MASTER-Kislovodsk | (23h 54m 43.10s , +04d 59m 36.3s) | C | 60 | 17.1 | 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/35621. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...