TITLE: GCN CIRCULAR NUMBER: 31941 SUBJECT: IceCube Alert 220424.05: Global MASTER-Net observations report DATE: 22/04/24 01:39:19 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, D. Vlasenko, G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D.Cheryasov, Ya.Kechin (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. Gres, N.M. Budnev (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),

A. Gabovich, V.Yurkov (Blagoveschensk Educational State University)

MASTER-Kislovodsk robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) was pointed to the IceCube Alert 220424.05 (trigger No 2186969,23h 03m 01.68s , +08d 51m 21.6s, R=0.66) errorbox 9 sec after notice time and 57 sec after trigger time at 2022-04-24 01:07:21 UT, with upper limit up to 14.9 mag. Observations started at twilight. The observations began at zenith distance = 73 deg. The sun altitude is -12.2 deg.

The galactic latitude b = -46 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=1952580

We obtain a following upper limits.

Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________

63 | 2022-04-24 01:07:21 | MASTER-Kislovodsk | (23h 02m 10.17s , +08d 33m 02.8s) | P| | 10 | 14.2 | 93 | 2022-04-24 01:07:51 | MASTER-Kislovodsk | (23h 02m 12.01s , +08d 34m 45.0s) | P| | 10 | 14.3 | 128 | 2022-04-24 01:08:21 | MASTER-Kislovodsk | (23h 02m 06.33s , +08d 33m 48.7s) | P| | 20 | 14.8 | 173 | 2022-04-24 01:09:01 | MASTER-Kislovodsk | (23h 02m 06.44s , +08d 34m 50.8s) | P| | 30 | 14.8 | 228 | 2022-04-24 01:09:51 | MASTER-Kislovodsk | (23h 02m 13.27s , +08d 33m 51.6s) | P| | 40 | 14.9 |

The observation and reduction will continue. The message may be cited.