TITLE:   GCN CIRCULAR
NUMBER:  34063
SUBJECT: LIGO/Virgo S230621bq: Global MASTER-Net observations report
DATE:    23/06/22 14:30:16 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) started inspect of the LIGO/Virgo S230621bq errorbox  15 sec after notice time and 785 sec after trigger time at 2023-06-22 00:00:48 UT, with upper limit up to  17.4 mag. Observations started at twilight.  The observations began at zenith distance = 62 deg. The sun  altitude  is -13.1 deg. 

The galactic latitude b = -16 deg., longitude l = 144 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/ligo_1.php?id=12218

We obtain a following upper limits.  

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

     865 | 2023-06-22 00:00:48 |   MASTER-Kislovodsk | (02h 45m 42.84s , +41d 55m 00.9s) |   C |   160 | 17.0 |        
    1056 | 2023-06-22 00:03:48 |   MASTER-Kislovodsk | (02h 45m 43.00s , +41d 53m 31.6s) |   C |   180 | 17.4 |        
    1256 | 2023-06-22 00:07:09 |   MASTER-Kislovodsk | (02h 45m 45.48s , +41d 55m 03.9s) |   C |   180 | 16.7 |        
Filter C is a clear (unfiltred) band. 


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