TITLE: GCN CIRCULAR NUMBER: 20715 SUBJECT: LIGO/Virgo G274296: Global MASTER Net PSN and QSO detection DATE: 17/02/21 23:08:53 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V.M. Lipunov, E. Gorbovskoy, T.Pogrosheva, N.Tyurina, P.Balanutsa, V.Shumkov, V. Kornilov, A.Kuznetsov, M.I.Panchenko, A.V.Krylov, I.Gorbunov Lomonosov Moscow State University, Sternberg Astronomical Institute N.M. Budnev, O. Gress, K. Ivanov, S.Yazev Irkutsk State University R.Podesta, C.Lopez, F. Podesta Observatorio Astronomico Felix Aguilar (OAFA) , National University of San Juan, Argentina H. Levato, C. Saffe Instituto de Ciencias Astronomicas,de la Tierra y del Espacio (ICATE), San Juan, Argentina D.Buckley, S. Potter, M. Kotze, South African Astronomical Observatory R. Rebolo, M. Serra-Ricart, G. Israelian, N.Lodiu The Instituto de Astrofisica de Canarias A. Tlatov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory V.Yurkov, Yu.Sergienko, A.Gabovich Blagoveschensk Educational State University, Blagoveschensk During inspection of LIGO event G274296 (Shawhan et al. GCN20689, Lipunov et al. GCN20696, GCN20712) MASTER-Tunka detected the following additional optical transients: 1) MASTER OT J144935.82+343749.9 discovery - PSN (18.0m) in SDSS galaxy(r=20.9) During GW inspection survey MASTER-Tunka auto-detection system discovered OT source at (RA, Dec) = 14h 49m 35.82s +34d 37m 49.9s on 2017-02-21.77409UT. The OT unfiltered magnitude is 18.0m (mlimit 19.4m). The OT is seen in 2 images. There is no minor planet at this place. There is SDSS galaxy with red m=20.94 http://skyserver.sdss.org/dr9/en/tools/quicklook/quickobj.asp?id=1237662226228118204 We have reference image without OT on 2016-12-05.94591 UT with unfiltered magnitude limit m=20.0m. Spectral observations are required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/144935.82343749.9.png MASTER OT J082950.02+274024.3 - possibly QSO outburst During GW inspection survey MASTER-Tunka auto-detection system discovered OT source at (RA, Dec) = 08h 29m 50.02s +27d 40m 24.3s on 2017-02-21.56417 UT. The OT unfiltered magnitude is 19.1m (limit 20.1m). The OT is seen in 3 images. There is no minor planet at this place. We have reference image without OT on 2015-11-19.71169 UT with unfiltered magnitude limit m=20.1m. There is GALEX source in 0.8" and this OT is in 1" from SDSS DR10 catalogue of candidate quasars (Brescia+, 2015), i.e. our OT is QSO in outburst. Spectral observations are required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/082950.02274024.3.png