TITLE: GCN CIRCULAR NUMBER: 24509 SUBJECT: LIGO/Virgo S190510g: MASTER OT detection inside PGC087378 galaxy DATE: 19/05/12 20:26:08 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, N.Tyurina, E. Gorbovskoy, V.Kornilov, D.Vlasenko, P.Balanutsa,D.Vlasenko, V.Vladimirov, D.Zimnukhov, A.Kuznetsov, P.Balanutsa, I.Gorbunov, A. Chasovnikov, F.Balakin, 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), D. Buckley (South African Astronomical Observatory), A. Tlatov, V.Senik, A.V. Parhomenko, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), 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) O. Gress, N.M. Budnev, O.Ershova (Applied Physics Institute, Irkutsk Stat University), V. Yurkov, A. Gabovich, Yu. Sergienko, D. Kobcev (Blagoveschensk EducationState University), MASTER OT J135130.87-525534.4 (2019fcc) - OT inside PGC087378 MASTER-OAFA auto-detection system ( Lipunov et al., "MASTER Global Robotic Net", Advances in Astronomy, 2010, 30L ) discovered OT source at (RA, Dec) = 13h 51m 30.87s -52d 55m 34.4s on 2019-05-12.29047 UT. The OT unfiltered magnitude is ~ 17m (mlim=18.4m). The OT is seen in 2 images. There is no minor planet at this place. We have reference image without OT on 2016-07-06.02547 UT with magnitude limit in 'clear' filter 19.0m. THe OT offset from center of the PGC087378 galaxy is 2.1E 11S. The distance is about ~50Mpc. The same transient we see 12 hours after trigger time in MASTER-SAAO database. Folow up observations are required.