TITLE:   GCN CIRCULAR
NUMBER:  40152
SUBJECT: IceCube-250416A: Global MASTER-Net observations report
DATE:    25/04/16 18:39:53 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>

V.Lipunov, E.Gorbovskoy, N.Tiurina,  P.Balanutsa, , D.Vlasenko, I.Panchenko,
A.Kuznetsov,  G.Antipov,  A.Sankovich, A.Sosnovskij, Yu.Tselik, M.Gulyaev, 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. 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 250416.77 (trigger No 37236133,05h 32m 21.84s , +15d 26m 27.6s, R=0.51) errorbox  18 sec after notice time and 81 sec after trigger time at 2025-04-16 18:33:36 UT, with upper limit up to  17.1 mag. The observations began at zenith distance = 75 deg. The sun  altitude  is -29.8 deg. 

The galactic latitude b = -9 deg., longitude l = 190 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2845236

We obtain a following upper limits.  

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

      92 | 2025-04-16 18:33:36 |         MASTER-SAAO | (05h 31m 59.71s , +15d 20m 12.0s) |   C |    20 | 17.0 |        
     131 | 2025-04-16 18:34:15 |         MASTER-SAAO | (05h 32m 00.24s , +15d 20m 15.4s) |   C |    20 | 17.0 |        
     175 | 2025-04-16 18:34:54 |         MASTER-SAAO | (05h 32m 00.81s , +15d 20m 18.5s) |   C |    30 | 17.1 |        
Filter C is a clear (unfiltred) band. 


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