TITLE:   GCN CIRCULAR
NUMBER:  24338
SUBJECT: LIGO/Virgo S190425z: MASTER detection of the faint flare in SDSS Seyfert  galaxy z = 0.09
DATE:    19/04/29 07:37:07 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, N.Tyurina, E. Gorbovskoy, V.Kornilov, D.Vlasenko, V.Vladimirov, 
D.Zimnukhov, A.Kuznetsov, P.Balanutsa, I.Gorbunov, A. Chasovnikov, 
V.Grinshpun, F.Balakin, A.Chasovnikov (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),

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

D. Buckley (South African Astronomical Observatory),

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

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

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

Global MASTER-Net (http://observ.pereplet.ru, Lipunov et al., 2010, Advances in 
Astronomy, vol. 2010, 30L)   started inspect of the LIGO/Virgo S190425z 
errorbox (Singer et al. GCN 24168) 3133 sec after trigger time at 2019-04-25 
09:10:18 UT  (Lipunov et al. GCN 24167).

After reviewing 25% of total probability, we found several possible 
transients. The most interesting is the MASTER OT J155829.22+271714.6.
Most likely this flash is related to the activity of the galaxy nuclear. 
Too large  redshift s = 0.09 (distance ~380 Mpc) excludes OT from possible 
candidates for a gravitational-wave event LIGO/Virgo S190425z.


MASTER OT J155829.22+271714.6  - Optical Flare in Active Seyfert Galaxy


MASTER-IAC (Teide Observatory, IAC, Tenerife, Spain) auto-detection system 
discovered OT source at (RA, Dec) = 15h 58m 29.22s +27d 17m 14.63s
2019-04-25 23:42:39.4 UT.
The OT unfiltered magnitude is 18.4m (limit 19.7 m).
  There is no minor planet at this place.
The discovery, referenceand differences images are available at
http://observ.pereplet.ru/images/MASTEROTJ155829.22+271714.6.jpg

The message may be cited.