GCN Circular 36679

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-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) started inspect of the Fermi GRB240616.38 (trigger No 740221779,16h 11m 55.20s , +02d 21m 00.0s, R=5.72) errorbox  30621 sec after notice time and 30655 sec after trigger time at 2024-06-16 17:40:30 UT, with upper limit up to  18.3 mag. The observations began at zenith distance = 58 deg. The sun  altitude  is -24.5 deg. 

The galactic latitude b = 35 deg., longitude l = 15 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2495751

We obtain a following upper limits.  

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

   30686 | 2024-06-16 17:40:30 |         MASTER-SAAO | (16h 05m 08.16s , +01d 14m 39.9s) |   C |    60 | 17.7 |        
   30765 | 2024-06-16 17:41:49 |         MASTER-SAAO | (16h 13m 15.12s , +01d 14m 30.8s) |   C |    60 | 17.6 |        
   31194 | 2024-06-16 17:48:58 |         MASTER-SAAO | (16h 06m 28.56s , +03d 08m 46.2s) |   C |    60 | 18.0 |        
   31273 | 2024-06-16 17:50:18 |         MASTER-SAAO | (16h 14m 26.17s , +03d 09m 59.9s) |   C |    60 | 17.9 |        
   31699 | 2024-06-16 17:57:24 |         MASTER-SAAO | (16h 05m 14.82s , +01d 15m 40.7s) |   C |    60 | 18.1 |        
   31779 | 2024-06-16 17:58:43 |         MASTER-SAAO | (16h 13m 09.49s , +01d 14m 29.6s) |   C |    60 | 18.0 |        
   32207 | 2024-06-16 18:05:51 |         MASTER-SAAO | (16h 06m 22.09s , +03d 09m 39.7s) |   C |    60 | 18.0 |        
   32286 | 2024-06-16 18:07:10 |         MASTER-SAAO | (16h 14m 23.19s , +03d 10m 28.1s) |   C |    60 | 18.2 |        
   32711 | 2024-06-16 18:14:16 |         MASTER-SAAO | (16h 05m 13.79s , +01d 16m 37.3s) |   C |    60 | 18.3 |        
   32791 | 2024-06-16 18:15:35 |         MASTER-SAAO | (16h 13m 07.59s , +01d 15m 32.4s) |   C |    60 | 18.3 |        
   33217 | 2024-06-16 18:22:41 |         MASTER-SAAO | (16h 06m 24.70s , +03d 10m 22.2s) |   C |    60 | 18.0 |        
   33296 | 2024-06-16 18:24:00 |         MASTER-SAAO | (16h 14m 25.36s , +03d 08m 52.0s) |   C |    60 | 18.3 |        
Filter C is a clear (unfiltred) band. 


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