TITLE:   GCN CIRCULAR
NUMBER:  25105
SUBJECT: MASTER OT detection inside LIGO/Virgo S190718y error box
DATE:    19/07/19 15:15:45 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, E. Gorbovskoy, N.Tyurina , P.Balanutsa,  F.Balakin, 
V.Kornilov,  D.Vlasenko,  V.Vladimirov, D.Zimnukhov, A.Kuznetsov, 
I.Gorbunov, A. Chasovnikov, V.Grinshpun, T.Pogrosheva (Lomonosov
Moscow State University, SAI, Physics Department),

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres (The 
Instituto de Astrofisica de Canarias),

R. Podesta, C. Lopez, C.Francile, F. Podesta (Observatorio Astronomico 
Felix Aguilar OAFA, San Juan National University),

D. Buckley (South African Astronomical Observatory),

A. Tlatov, V.Senik, A.V. Parhomenko, D. Dormidontov
(Kislovodsk Solar Station of the Pulkovo Observatory),

H.Levato
(Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE,SJNU)

O. Gress, N.M. Budnev, O.Ershova
(Applied Physics Institute, Irkutsk Stat University),

V. Yurkov, A. Gabovich, Yu. Sergienko, D. Kobcev
(Blagoveschensk   Education State University),

MASTER OT J203053.79+384020.1 / AT2019lly discovery

MASTER-IAC auto-detection system discovered OT source at
(RA, Dec) = 20h 30m 53.79s +38d 40m 20.1s on 2019-07-18.92684 UT.

The OT unfiltered magnitude is 14.9m (limit 19.4m).

The OT is seen in 2 images. There is no minor planet at this place.
We have reference image without OT on 2019-07-09.14716 UT with unfiltered
magnitude limit 19.7m.

The discovery and reference images are available at:
http://master.sai.msu.ru/static/OT/203053.79384020.1.png

There is a DSS  source inside 2" with mag = 20.0m.
This flash is registered in the error box GW S190718y,but is probably 
unrelated to the GW event (Cataclysmic Variable)

MASTER cover map of Ligo/Virgo S190718y error-field inspection  will be
available on-line at:
https://master.sai.msu.ru/site/master2/ligo_1.php?id=10491

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