TITLE:   GCN CIRCULAR
NUMBER:  34010
SUBJECT: LIGO/Virgo S230618s: Global MASTER-Net observations report
DATE:    23/06/19 00:36:41 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 S230618s errorbox  53365 sec after notice time and 53473 sec after trigger time at 2023-06-19 00:26:29 UT, with upper limit up to  12.2 mag. The observations began at zenith distance = 73 deg. The sun  altitude  is -34.7 deg. 

The galactic latitude b =  9 deg., longitude l = 259 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/ligo_1.php?id=12106

We obtain a following upper limits.  

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

     729 | 2023-06-18 09:45:54 |             MASTER- | (17h 51m 49.23s , +08d 33m 20.4s) |   C |   180 | 18.5 |        
    1069 | 2023-06-18 09:51:35 |             MASTER- | (17h 59m 55.36s , +08d 32m 17.8s) |   C |   180 | 18.6 |        
    1411 | 2023-06-18 09:57:17 |             MASTER- | (17h 51m 47.13s , +08d 30m 60.0s) |   C |   180 | 18.5 |        
    1758 | 2023-06-18 10:03:04 |             MASTER- | (17h 59m 59.19s , +08d 31m 10.8s) |   C |   180 | 18.5 |        
    2649 | 2023-06-18 10:17:54 |             MASTER- | (17h 57m 53.00s , +10d 25m 32.8s) |   C |   180 | 18.5 |        
    3330 | 2023-06-18 10:29:16 |             MASTER- | (18h 06m 02.32s , +10d 23m 17.9s) |   C |   180 | 18.3 |        
    4221 | 2023-06-18 10:44:06 |             MASTER- | (17h 57m 57.43s , +10d 21m 56.4s) |   C |   180 | 18.3 |        
    4904 | 2023-06-18 10:55:29 |             MASTER- | (18h 06m 03.59s , +10d 22m 18.7s) |   C |   180 | 18.0 |        
    6681 | 2023-06-18 11:25:06 |             MASTER- | (17h 47m 06.59s , +06d 29m 48.5s) |   C |   180 | 16.5 |        
   53564 | 2023-06-19 00:26:29 |         MASTER-OAFA | (08h 17m 30.62s , -17d 12m 38.4s) |   C |   180 | 12.3 |        
Filter C is a clear (unfiltred) band. 


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