TITLE: GCN CIRCULAR NUMBER: 15983 SUBJECT: GRB 140311C: MASTER optical observations DATE: 14/03/14 15:01:38 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs E. Gorbovskoy, V. Lipunov, M. Pruzhinskaya, D.Denisenko, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, V.V.Chazov, D.Kuvshinov Lomonosov Moscow State University, Sternberg Astronomical Institute V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov Blagoveschensk Educational State University, Blagoveschensk K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk Irkutsk State University A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory V.Krushinski, I.Zalozhnih, A. Popov Ural Federal University, Kourovka 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) As previously reported (Yurkov et. al. GCN 15981) MASTER VWF robotic very wide field cameras (FOV=2x384 square degrees, D=72mm, f/1.2, 1 pix = 22 arcsec) installed on MASTER-II robotic telescope in Tunka covered full FERMI GBM error-box (M. Stanbro, GCN15977) before, during and after GRB. We haven`t found credible optical transient with 3-sigma upper limit 10.5m. We also didn't find credible optical counterpart on the survey (Yurkov et. al. GCN 15981) of part of error box carried out directly after GRB on MASTER-II robotic telescope up to 18 mag. The synchronous move of FERMI GBM error-box available here http://master.sai.msu.ru/static/GRB/GRB140311C_FERMI.gif http://master.sai.msu.ru/static/GRB/GRB140311C_diff.gif The circle on move is the Fermi GBM 1 sigma+3 degrees systematic error box. Also very wide field cameras covered a place of possible iPTF counterpart (Singer et. al. GCN 15971). Unfortunately the bright star is projected into OT place. We didn't find a noticeable brightening of this star. The syncronous move from very wide field cameras of possible iPTF counterpart place available here http://master.sai.msu.ru/static/GRB/GRB140311C_IPTF.gif This place was not covered on MASTER-II survey. The Prompt Optical to Gamma Fluence Ratio during this burst is: F_opt/F_gamma <~ 1 : 820. The covarege map is available at http://master.sai.msu.ru/static/GRB/GRB140311C_map1.png . The message may be cited.