GCN Circular 36917

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-Amur robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Russia (Blagoveshchensk State Pedagogical University) was pointed to the IceCube Alert 240721.68 (trigger No 30853199,23h 39m 46.30s , +22d 32m 05.6s, R=0.551) errorbox  17 sec after notice time and 68 sec after trigger time at 2024-07-21 16:18:34 UT, with upper limit up to  15.1 mag. The observations began at zenith distance = 44 deg. The sun  altitude  is -19.0 deg. 

The galactic latitude b = -37 deg., longitude l = 103 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2537168

We obtain a following upper limits.  

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

      74 | 2024-07-21 16:18:34 |         MASTER-Amur | (23h 40m 47.12s , +22d 28m 12.2s) |  P\ |    10 | 14.6 |        
     112 | 2024-07-21 16:19:07 |         MASTER-Amur | (23h 40m 41.34s , +22d 27m 32.9s) |  P\ |    20 | 13.9 |        
     157 | 2024-07-21 16:19:47 |         MASTER-Amur | (23h 40m 42.01s , +22d 28m 29.5s) |  P\ |    30 | 15.1 |        
     217 | 2024-07-21 16:20:42 |         MASTER-Amur | (23h 40m 48.26s , +22d 27m 23.3s) |  P\ |    40 | 15.1 |        


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