GCN Circular 45786

Subject
IceCube Alert 260930A: Global MASTER-Net observations report
Date
2026-09-30T01:01:00Z (10 hours ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
Via
M. Segura,  F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA)

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 (Lomonosov MSU)

D.Buckley (SAAO),

A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity)
A.Sosnovskij (Lomonosov MSU)

A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory)

L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez,
A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory)

R.Rebolo (The Instituto de Astrofisica de Canarias)

O.Gress, N.Budnev(ISU)


MASTER-OAFA robotic telescope  [1]  located in Argentina (OAFA observatory of San Juan National University) was pointed to the IceCube Alert 260930A (trigger No 36103697,15h 42m 20.88s , +00d 58m 08.4s, R=0.66) errorbox  52 sec after notice time and 95 sec after trigger time at 2026-09-30 00:46:18 UT, with upper limit up to  16.2 mag. The observations began at zenith distance = 78 deg. The sun  altitude  is -27.6 deg. 

The galactic latitude b = 41 deg., longitude l =  8 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=3515330

We obtain a following upper limits.  

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

     106 | 2026-09-30 00:46:18 |         MASTER-OAFA | (15h 41m 38.97s , +01d 07m 27.5s) |   C |    20 | 15.8 |        
     131 | 2026-09-30 00:46:44 |         MASTER-OAFA | (15h 41m 38.94s , +01d 07m 28.3s) |   C |    20 | 15.8 |        
     162 | 2026-09-30 00:47:10 |         MASTER-OAFA | (15h 41m 38.90s , +01d 07m 28.8s) |   C |    30 | 16.1 |        
     203 | 2026-09-30 00:47:46 |         MASTER-OAFA | (15h 41m 38.84s , +01d 07m 29.1s) |   C |    40 | 16.2 |        
     254 | 2026-09-30 00:48:32 |         MASTER-OAFA | (15h 41m 38.86s , +01d 07m 29.2s) |   C |    50 | 15.7 |        
     316 | 2026-09-30 00:49:29 |         MASTER-OAFA | (15h 41m 38.82s , +01d 07m 29.8s) |   C |    60 | 15.5 |        
     387 | 2026-09-30 00:50:35 |         MASTER-OAFA | (15h 41m 38.85s , +01d 07m 30.0s) |   C |    70 | 15.8 |        
     473 | 2026-09-30 00:51:51 |         MASTER-OAFA | (15h 41m 38.39s , +01d 07m 34.4s) |   C |    90 | 14.5 |        
Filter C is a clear (unfiltred) band. 


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

[1] - V.M. Lipunov, V.G. Kornilov, E.S. Gorbovskoy, N.A. Tiurina & A.S.Kuznetsov, 2023,  Astronomical Robotic Networks and Operative Multichanel Astrophysics, Lomonosov MSU PRESS, 591pp.
http : // www.pereplet.ru/lipunov/625.html