TITLE:   GCN CIRCULAR
NUMBER:  37874
SUBJECT: Fermi GRB 241025A: Global MASTER-Net observations report
DATE:    24/10/25 11:15:35 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-Tunka robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Russia (Applied Physics Institute, Irkutsk State University) started inspect of the Fermi GRB 241025A ( Fermi GBM team, GCN 37860) errorbox  33528 sec after notice time and 33571 sec after trigger time at 2024-10-25 10:55:58 UT, with upper limit up to  18.6 mag. Observations started at twilight.  The observations began at zenith distance = 34 deg. The sun  altitude  is -10.3 deg. 

The galactic latitude b = 20 deg., longitude l = 116 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2648590

We obtain a following upper limits.  

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

   33587 | 2024-10-25 10:55:58 |        MASTER-Tunka | (22h 21m 51.83s , +83d 24m 29.9s) |   C |    30 | 17.7 |        
   33630 | 2024-10-25 10:56:41 |        MASTER-Tunka | (22h 21m 57.07s , +83d 23m 31.1s) |   C |    30 | 17.7 |        
   33674 | 2024-10-25 10:57:25 |        MASTER-Tunka | (22h 21m 50.77s , +83d 22m 33.0s) |   C |    30 | 17.8 |        
   33716 | 2024-10-25 10:58:08 |        MASTER-Tunka | (22h 21m 56.24s , +83d 22m 37.1s) |   C |    30 | 17.8 |        
   33860 | 2024-10-25 11:00:31 |        MASTER-Tunka | (22h 21m 59.88s , +83d 22m 43.0s) |   C |    30 | 18.1 |        
   33919 | 2024-10-25 11:01:27 |        MASTER-Tunka | (22h 22m 05.43s , +83d 24m 20.8s) |   C |    36 | 18.3 |        
   34038 | 2024-10-25 11:03:26 |        MASTER-Tunka | (22h 21m 56.61s , +83d 24m 43.0s) |   C |    36 | 18.6 |        
Filter C is a clear (unfiltred) band. 


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