GCN Circular 36420

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) started inspect of the Fermi GRB240509.72 (trigger No 736967879,16h 00m 40.80s , +18d 06m 00.0s, R=15.72) errorbox  347 sec after notice time and 383 sec after trigger time at 2024-05-09 17:24:17 UT, with upper limit up to  15.6 mag. The observations began at zenith distance = 43 deg. The sun  altitude  is -17.7 deg. 

The galactic latitude b = 45 deg., longitude l = 32 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2449743

We obtain a following upper limits.  

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

     413 | 2024-05-09 17:24:17 |         MASTER-Amur | (16h 11m 49.20s , +08d 46m 12.2s) |   C |    60 | 15.0 |        
     413 | 2024-05-09 17:24:17 |         MASTER-Amur | (16h 04m 17.74s , +08d 17m 48.2s) |   C |    60 | 14.1 |        
     506 | 2024-05-09 17:25:50 |         MASTER-Amur | (16h 07m 16.74s , +06d 53m 00.3s) |   C |    60 | 15.3 |        
     506 | 2024-05-09 17:25:50 |         MASTER-Amur | (15h 59m 48.04s , +06d 24m 24.6s) |   C |    60 | 14.2 |        
     600 | 2024-05-09 17:27:23 |         MASTER-Amur | (16h 17m 35.39s , +10d 40m 08.5s) |   C |    60 | 15.3 |        
     600 | 2024-05-09 17:27:23 |         MASTER-Amur | (16h 10m 00.66s , +10d 11m 38.7s) |   C |    60 | 14.3 |        
     693 | 2024-05-09 17:28:57 |         MASTER-Amur | (16h 02m 00.74s , +10d 38m 24.2s) |   C |    60 | 15.5 |        
     693 | 2024-05-09 17:28:57 |         MASTER-Amur | (15h 54m 26.43s , +10d 09m 54.2s) |   C |    60 | 14.2 |        
     901 | 2024-05-09 17:32:24 |         MASTER-Amur | (16h 08m 47.19s , +12d 34m 14.1s) |   C |    60 | 15.6 |        
     901 | 2024-05-09 17:32:24 |         MASTER-Amur | (16h 01m 08.54s , +12d 06m 01.6s) |   C |    60 | 14.6 |        
     994 | 2024-05-09 17:33:57 |         MASTER-Amur | (16h 22m 39.63s , +06d 51m 24.9s) |   C |    60 | 15.3 |        
     994 | 2024-05-09 17:33:57 |         MASTER-Amur | (16h 15m 10.60s , +06d 22m 38.6s) |   C |    60 | 14.5 |        
    1087 | 2024-05-09 17:35:31 |         MASTER-Amur | (16h 27m 19.36s , +08d 47m 11.9s) |   C |    60 | 15.1 |        
    1087 | 2024-05-09 17:35:31 |         MASTER-Amur | (16h 19m 47.57s , +08d 18m 28.0s) |   C |    60 | 13.6 |        
    1204 | 2024-05-09 17:37:27 |         MASTER-Amur | (16h 03m 52.48s , +04d 57m 22.4s) |   C |    60 | 15.4 |        
    1204 | 2024-05-09 17:37:27 |         MASTER-Amur | (15h 56m 26.29s , +04d 28m 21.9s) |   C |    60 | 14.4 |        
    1297 | 2024-05-09 17:39:01 |         MASTER-Amur | (16h 19m 07.29s , +04d 58m 56.4s) |   C |    60 | 15.5 |        
Filter C is a clear (unfiltred) band. 


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