TITLE: GCN CIRCULAR NUMBER: 17676 SUBJECT: Fermi trigger 449861706: MASTER-SAAO possible candidate to OT of Short GRB DATE: 15/04/04 22:24:45 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs N.Tyurina, E. Gorbovskoy, V. Lipunov, V.Kornilov, D.Kuvshinov, P.Balanutsa, A.Kuznetsov, D.Denisenko Lomonosov Moscow State University, Sternberg Astronomical Institute, Moscow State University D.Buckley, S. Potter, A.Kniazev, M.Kotze South African Astronomical Observatory K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk Irkutsk State University V.Krushinsky, I.Zalozhnih, A. Popov Ural Federal University, Yekaterinburg, Kourovka V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov Blagoveschensk Educational State University, Blagoveschensk A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory Hugo Levato and Carlos Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE) Claudio Mallamaci, Carlos Lopez and Federico Podest Observatorio Astronomico Felix Aguilar (OAFA) MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in SAAO was pointed to the GRB150404.73 (Fermi trigger 449861706) 8 sec after notice time and 41 sec after trigger time at 2015-04-04 17:35:45 UT. On our first (10s exposure) set we found 1 optical transient within FERMI error-box (ra=11 05 45 dec=-69 34 46 r=9.720000) in one polarization: MASTER OT J110859.75-693818.9 RA = 11h 08m 59.75s Dec = -69d 38m 18s.9 m_OT=14.8. We have 2 pair images in 2 different polarization. The first pair started 2015-04-04 17:35:45 , 10s exposition. The second pair (20-s exposition) started on 2015-04-04 17:36:25, and there is no optical candidate on it. The 5-sigma upper limit has been about 15.8 mag. The possible OT image is available at http://observ.pereplet.ru/GRB150404.73.jpg The message may be cited.