TITLE: GCN CIRCULAR NUMBER: 16288 SUBJECT: GRB 140516A: MASTER early optical observations DATE: 14/05/17 01:13:41 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs E. Gorbovskoy, V. Lipunov, V.Kornilov, D.Kuvshinov, A.Belinski, N.Tyurina, N.Shatskiy, P.Balanutsa, D.Zimnukhov, A.Kuznetsov, V.V.Chazov, D.Denisenko, A.Sankovich Lomonosov Moscow State University, Sternberg Astronomical Institute, Moscow State University A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory 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 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) MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in Kislovodsk was pointed to the GRB140516A 22 sec after notice time 44 sec after trigger time at 2014-05-16 20:31:39 UT in two polarizations. On our first (10s exposure) set we haven`t found optical transient within SWIFT error-box (Bernardini et. al GCN 16285). The 5-sigma upper limit has been about 17.0 mag. As we have a set of observations after that with exposures from 10 to 180 seconds during several hours. In table 1 some limits are provided. Table 1 ------- T_start Exptime T-T_mead T-T_start T-T_stop Filter mlimit Coadd 2014-05-16 20:31:39 10 49 sec 44 sec 54 sec P| 17.0 1 2014-05-16 20:31:39 10 49 sec 44 sec 54 sec P- 16.9 1 2014-05-16 20:31:39 780 466 sec 44 sec 889 sec P| 19.6 13* 2014-05-16 20:31:39 780 466 sec 44 sec 889 sec P| 19.3 13* 2014-05-16 20:45:54 3600 2914 sec 899 sec 4930 sec P| 20.6 20 2014-05-16 20:45:54 3600 2914 sec 899 sec 4930 sec P- 20.4 20 2014-05-16 20:45:54 7200 2914 sec 899 sec 4930 sec P| + P- 21.0 40** --------------------------------------------------------------------------------- * This is a set images with diffrent exposure times from 10 to 180 seconds. ** We has images synchronously in 2 channels. Therefore we can increase twice exptime in case of constant t_start and t_stop. P- and P| is a polarization filter which are oriented at an angle 0 and 90 degrees to RA axis respectivel. T is a GRB trigger time. The message may be cited.