TITLE: GCN CIRCULAR NUMBER: 25791 SUBJECT: GRB 190919B: MASTER OT early detection at GROND position DATE: 19/09/20 07:30:40 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs N.Tyurina, V. Lipunov, E. Gorbovskoy, V.Kornilov, F.Balakin, P.Balanutsa,A.Kuznetsov, V.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov,V.Senik, T.Pogrosheva, K.Pozdnyakov, A.Chasovnikov, V.Topolev, D.Kuvshinov(Lomonosov Moscow State University, SAI, Physics Department), R. Podesta, C.Lopez, F. Podesta, C.Francile(Observatorio Astronomico Felix Aguilar OAFA), H.Levato(Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE), R. Rebolo, M. Serra(The Instituto de Astrofisica de Canarias), D. Buckley(South African Astronomical Observatory), O.A. Gres, N.M. Budnev, O.Ershova(Irkutsk State University, API), A. Tlatov, D. Dormidontov(Kislovodsk Solar Station of the Pulkovo Observatory), V. Yurkov, A. Gabovich, Yu. Sergienko(Blagoveschensk Educational State University) We see GRB190919B (INTEGRAL trigger 8377; Mereghetti et al. GCN 25788) at prompt and afterglow stage with flare (after 7 min) on several MASTER telescopes (Lipunov et al., GCN 25787) at GROND position (Bolmer et al, 25789). Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/event.php?id=1136619 The OT coordinates are: RA, Dec = 20h 47m 30.56s , -44d 41m 42s.5 Error = 0.3 arcsec The observation and reduction will be continued. The message may be cited.