TITLE:   GCN CIRCULAR
NUMBER:  33909
SUBJECT: LIGO/Virgo S230603aa: Global MASTER-Net observations report
DATE:    23/06/03 07:48:51 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-OAFA robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Argentina (OAFA observatory of San Juan National University) started inspect of the LIGO/Virgo S230603aa errorbox  52 sec after notice time and 121 sec after trigger time at 2023-06-03 07:36:46 UT, with upper limit up to  16.3 mag. The observations began at zenith distance = 80 deg. The sun  altitude  is -48.2 deg. 

The galactic latitude b = 34 deg., longitude l = 66 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/ligo_1.php?id=11930

We obtain a following upper limits.  

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

     132 | 2023-06-03 07:36:46 |         MASTER-OAFA | (17h 16m 22.77s , +41d 22m 00.9s) |   C |    20 | 15.9 |        
     188 | 2023-06-03 07:37:38 |         MASTER-OAFA | (17h 16m 20.68s , +41d 23m 37.1s) |   C |    30 | 16.0 |        
     254 | 2023-06-03 07:38:39 |         MASTER-OAFA | (17h 16m 20.54s , +41d 22m 11.6s) |   C |    40 | 16.3 |        
Filter C is a clear (unfiltred) band. 


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