TITLE: GCN CIRCULAR NUMBER: 26991 SUBJECT: Swift GRB200205.81: Global MASTER-Net OT detection DATE: 20/02/05 19:32:33 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs D. Buckley, S. Potter, A. Kniazev, M. Kotze South African Astronomical Observatory V. Lipunov, E. Gorbovskoy, V.Kornilov, D.Kuvshinov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, F. Balakin Lomonosov Moscow State University, Sternberg Astronomical Institute, Moscow State University K. Ivanov, O. Gres, N.M. Budnev, S. Yazev, O. Chuvalaev, V. Poleshchuk Irkutsk State University A. Tlatov, V.Senik, A.V. Parhomenko, D. Dormidontov Kislovodsk Solar Station of the Pulkovo Observatory V. Yurkov, A. Gabovich, Yu. Sergienko Blagoveschensk Educational State University, Blagoveschensk R. Podesta, Carlos Lopez and F. Podesta Observatorio Astronomico Felix Aguilar (OAFA) Hugo Levato Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE) R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres The Instituto de Astrofisica de Canarias MASTER-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) was pointed to the GRB200205.81 21 sec after notice time and 300 sec after trigger time at 2020-02-05 19:26:44 UT. On our first (60s exposure) set we found 1 optical transient within Swift error-box (ra=107.8 dec=-56.4808 r=0.05) brighter than 15.7. T-Tmid Date Time Expt. Ra Dec Mag ---------|---------------------|-------|-----------------|-----------------|------- 330 2020-02-05 19:26:44 60 (07h 11m 09.07s , -56d 29m 14.6s) 16.3 The 5-sigma upper limit has been about 15.7mag The message may be cited.