TITLE:   GCN CIRCULAR
NUMBER:  33692
SUBJECT: Swift GRB230427.44: Global MASTER-Net observations report
DATE:    23/04/27 17:29:52 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, 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-Kislovodsk robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) was pointed to the Swift GRB230427.44 (trigger No 1165948,10h 13m 17.76s , +48d 10m 48.0s, R=0.05) errorbox  24243 sec after notice time and 24285 sec after trigger time at 2023-04-27 17:16:37 UT, with upper limit up to  19.0 mag. Observations started at twilight.  The observations began at zenith distance =  6 deg. The sun  altitude  is -12.4 deg. 

The galactic latitude b = 53 deg., longitude l = 168 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2213007

We obtain a following upper limits.  

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

   24376 |   MASTER-Kislovodsk |   C |   180 | 18.3 |        
   24376 |   MASTER-Kislovodsk |   C |   180 | 18.8 |        
   24576 |   MASTER-Kislovodsk |   C |   180 | 18.6 |        
   24576 |   MASTER-Kislovodsk |   C |   180 | 19.0 |        
Filter C is a clear (unfiltred) band. 


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