GCN Circular 33463

V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, 
G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov,  D.Cheryasov, Ya.Kechin
(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. Gres, N.M. Budnev
(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),

A. Gabovich, V.Yurkov 
(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) was pointed to the Swift GRB230311.85 (trigger No 1159442,04h 39m 55.66s , +44d 40m 25.7s, R=0.05) errorbox  51098 sec after notice time and 51190 sec after trigger time at 2023-03-12 10:36:15 UT, with upper limit up to  15.0 mag. Observations started at twilight.  The observations began at zenith distance = 18 deg. The sun  altitude  is -11.6 deg. 

The galactic latitude b = -1 deg., longitude l = 160 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2203815

We obtain a following upper limits.  

Tmid-T0  |          Site       |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________

   51281 |         MASTER-Amur |   C |   180 | 14.9 |        
   51680 |         MASTER-Amur |   C |   180 | 15.0 |        
Filter C is a clear (unfiltred) band. 


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