TITLE:   GCN CIRCULAR
NUMBER:  35644
SUBJECT: Fermi GRB 240127A: Global MASTER-Net observations report
DATE:    24/01/27 19:31:24 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-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 GRB 240127A ( Fermi GBM team, GCN 35641) errorbox  50416 sec after notice time and 50449 sec after trigger time at 2024-01-27 18:51:29 UT, with upper limit up to  18.4 mag. Observations started at twilight.  The observations began at zenith distance = 79 deg. The sun  altitude  is -13.5 deg. 

The galactic latitude b = -32 deg., longitude l = 334 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2365466

We obtain a following upper limits.  

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

   50479 | 2024-01-27 18:51:29 |         MASTER-SAAO | (21h 13m 34.50s , -48d 04m 39.1s) |   C |    60 | 17.2 |        
   50479 | 2024-01-27 18:51:29 |         MASTER-SAAO | (21h 16m 12.91s , -48d 17m 24.0s) |   C |    60 | 17.8 |        
   50559 | 2024-01-27 18:52:49 |         MASTER-SAAO | (21h 16m 07.54s , -49d 59m 45.4s) |   C |    60 | 17.3 |        
   50559 | 2024-01-27 18:52:49 |         MASTER-SAAO | (21h 18m 52.23s , -50d 12m 29.7s) |   C |    60 | 17.8 |        
   50719 | 2024-01-27 18:55:29 |         MASTER-SAAO | (21h 07m 19.93s , -55d 42m 11.5s) |   C |    60 | 17.8 |        
   50719 | 2024-01-27 18:55:29 |         MASTER-SAAO | (21h 10m 27.84s , -55d 54m 56.1s) |   C |    60 | 18.3 |        
   50878 | 2024-01-27 18:58:08 |         MASTER-SAAO | (21h 20m 12.47s , -51d 53m 49.9s) |   C |    60 | 17.8 |        
   50878 | 2024-01-27 18:58:08 |         MASTER-SAAO | (21h 23m 04.13s , -52d 06m 33.9s) |   C |    60 | 18.4 |        
   50957 | 2024-01-27 18:59:27 |         MASTER-SAAO | (19h 58m 01.24s , -59d 27m 21.3s) |   C |    60 | 17.2 |        
Filter C is a clear (unfiltred) band. 


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