TITLE: GCN CIRCULAR NUMBER: 24263 SUBJECT: Swift GRB190427.19 Global MASTER-Net observations report DATE: 19/04/27 05:31:26 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, E. Gorbovskoy, V.Kornilov, D.Kuvshinov, N.Tyurina, P.Balanutsa, A.Kuznetsov, V.V.Chazov, D. Vlasenko Lomonosov Moscow State University, Sternberg Astronomical Institute, Moscow State University A. Tlatov, V.Senik, A.V. Parhomenko, D. Dormidontov Kislovodsk Solar Station of the Pulkovo Observatory K. Ivanov, O. Gres, N.M. Budnev, S. Yazev, O. Chuvalaev, V. Poleshchuk Irkutsk State University 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 and Carlos Saffe 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 D. Buckley, S. Potter, A. Kniazev, M. Kotze South African Astronomical Observatory MASTER-IAC robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Spain (IAC Teide Observatory) was pointed to the Swift GRB190427.19 ( 18h 40m 51.12s , +40d 19m 19.20s, R=0.05) errorbox 40 sec after trigger time at 2019-04-27 04:34:54 UT, with upper limit up to 18.6 mag. The observations began at zenit distance = 16 deg. The sun altitude is -23.5 deg. MASTER-SAAO robotic telescope located in South Africa (South African Astronomical Observatory) was pointed to the Swift GRB190427.19 errorbox 44 sec after trigger time at 2019-04-27 04:34:58 UT, with upper limit up to 13.2 mag. Observations started at twilight. The observations began at zenit distance = 75 deg. The sun altitude is -7.5 deg. The galactic latitude b = -60 deg., longitude l = 98 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1004408 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 45 | MASTER-IAC | P- | 10 | 16.8 | 45 | MASTER-IAC | P| | 10 | 17.1 | 50 | MASTER-SAAO | P\ | 10 | 13.3 | 77 | MASTER-SAAO | P\ | 10 | 13.2 | 100 | MASTER-IAC | P- | 20 | 17.4 | 100 | MASTER-IAC | P| | 20 | 17.6 | 108 | MASTER-SAAO | P\ | 20 | 13.1 | 160 | MASTER-IAC | P- | 30 | 17.7 | 160 | MASTER-IAC | P| | 30 | 17.9 | 212 | MASTER-IAC | P- | 40 | 17.9 | 212 | MASTER-IAC | P| | 40 | 18.2 | 274 | MASTER-IAC | P- | 50 | 18.1 | 274 | MASTER-IAC | P| | 50 | 18.3 | 346 | MASTER-IAC | P- | 60 | 18.3 | 346 | MASTER-IAC | P| | 60 | 18.6 | The observation and reduction will continue. The message may be cited.