GCN Circular 36386

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 GRB240503.01 (trigger No 736387941,06h 27m 04.08s , +45d 57m 00.0s, R=31.88) errorbox  56538 sec after notice time and 56573 sec after trigger time at 2024-05-03 15:55:10 UT, with upper limit up to  16.9 mag. The observations began at zenith distance = 42 deg. The sun  altitude  is -23.9 deg. 

MASTER-SAAO robotic telescope  located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB240503.01 errorbox  67241 sec after notice time and 67276 sec after trigger time at 2024-05-03 18:53:32 UT, with upper limit up to  18.3 mag. The observations began at zenith distance = 66 deg. The sun  altitude  is -37.4 deg. 

The galactic latitude b = 16 deg., longitude l = 169 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2441460

We obtain a following upper limits.  

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

   56604 | 2024-05-03 15:55:10 |         MASTER-Amur | (09h 49m 01.30s , +65d 17m 46.7s) |   C |    60 | 16.8 |        
   57624 | 2024-05-03 16:12:10 |         MASTER-Amur | (09h 49m 09.76s , +65d 16m 15.3s) |   C |    60 | 16.9 |        
   58551 | 2024-05-03 16:27:37 |         MASTER-Amur | (09h 49m 20.02s , +65d 14m 40.7s) |   C |    60 | 16.5 |        
   67306 | 2024-05-03 18:53:32 |         MASTER-SAAO | (08h 15m 13.91s , +20d 21m 37.5s) |   C |    60 | 18.3 |        
   68109 | 2024-05-03 19:06:55 |         MASTER-SAAO | (07h 59m 12.05s , +20d 21m 22.5s) |   C |    60 | 14.4 |        
   68109 | 2024-05-03 19:06:55 |         MASTER-SAAO | (08h 01m 02.50s , +20d 08m 56.0s) |   C |    60 | 15.1 |        
   68189 | 2024-05-03 19:08:15 |         MASTER-SAAO | (08h 07m 39.33s , +20d 22m 59.2s) |   C |    60 | 14.1 |        
   68189 | 2024-05-03 19:08:15 |         MASTER-SAAO | (08h 09m 29.82s , +20d 10m 33.2s) |   C |    60 | 14.3 |        
   68821 | 2024-05-03 19:18:47 |         MASTER-SAAO | (08h 23m 37.38s , +22d 03m 16.3s) |   C |    60 | 17.9 |        
   69005 | 2024-05-03 19:21:51 |         MASTER-SAAO | (08h 01m 00.70s , +20d 10m 27.0s) |   C |    60 | 16.5 |        
   69096 | 2024-05-03 19:23:22 |         MASTER-SAAO | (08h 09m 29.76s , +20d 11m 28.2s) |   C |    60 | 17.6 |        
Filter C is a clear (unfiltred) band. 


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