TITLE: GCN CIRCULAR NUMBER: 20836 SUBJECT: Swift trigger 741567: MASTER red star flare detection DATE: 17/03/08 08:41:26 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs Natalia Tyurina (Main MASTER telegram editor, Lomonosov Moscow State University) V.M.Lipunov, E. Gorbovskoy, V.G.Kornilov, D.Kuvshinov, P.Balanutsa, A.Kuznetsov, V.V.Chazov, A.V.Krylov, I.Gorbunov Lomonosov Moscow State University, Sternberg Astronomical Institute, Moscow State University D.Buckley South African Astronomical Observatory V.Yurkov, A. Gabovich, Yu.Sergienko Blagoveschensk Educational State University, Blagoveschensk A. Tlatov, V.Senik, D. Dormidontov, A.V. Parhomenko, Kislovodsk Solar Station of the Pulkovo Observatory N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk, O. Ershova, K.Ivanov, S.Yazev Irkutsk State University R. Podesta, Carlos Lopez and Federico Podesta Observatorio Astronomico Felix Aguilar (OAFA) Hugo Levato and Carlos Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE) R. Rebolo, M. Serra, N. Lodieu, G. Israelian The Instituto de Astrofisica de Canarias MASTER-SAAO robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in SAAO was pointed to the SWIFT-BAT 741567 trigger 106 sec after trigger time at 2017-03-08 03:32:39 UT. On our 1-th (100s exposure) set we found 1 optical transient within SWIFT error-box (ra=260.067 dec=-24.8406 r=0.1) T-Tmid Date Time Expt. Ra Dec Mag ---------|---------------------|-------|-----------------|-----------------|------- 542 2017-03-08 03:32:39 100 (17h 20m 04.16s , -24d 47m 28.8s) 14.02 The 5-sigma upper limit has been about 17.4 mag There is USNO-B1 red star with R1=15.96,R2=17.44,B2=19.79,I=12.42, (J-K)=2.1 We have reference unfiltered image in MASTER-OAFA (Argentina) m = 16.6 . The detection images and reference image are available at master.sai.msu.ru/static/OT/MASTEROTJ172004.16-244728.8.jpg The message may be cited.