TITLE: GCN CIRCULAR NUMBER: 24034 SUBJECT: IceCube-190331A: MASTER optical follow-up observations DATE: 19/04/01 11:56:39 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, E. Gorbovskoy, N.Tyurina, V.Kornilov, D.Vlasenko, V.Vladimirov, D.Zimnukhov, A.Kuznetsov, P.Balanutsa, A. Chasovnikov, V.Topolev, F.Balakin, K.Zhirkov, D.Kuvshinov (Lomonosov Moscow State University, SAI, Physics Department), R. Podesta, C. Lopez, C.Francile, F. Podesta (Observatorio Astronomico Felix Aguilar OAFA, San Juan National University), H.Levato (Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE, SJNU) R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres (The Instituto de Astrofisica de Canarias), D. Buckley (South African Astronomical Observatory), O. Gress, N.M. Budnev, O.Ershova, S.Yazev (Applied Physics Institute, Irkutsk State University), V. Yurkov, A. Gabovich, Yu. Sergienko, D. Kobcev (Blagoveschensk Educational State University), A. Tlatov, V.Senik, A.V. Parhomenko, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), MASTER-OAFA robotic telescope (Global MASTER-Net http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy,vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) started inspect of IceCube 190331A error-box (Kopper et al. GCN24028, center RA,Dec=337.68deg, -20.70deg) at 2019-04-01 09:04:32UT (when error-box_altitude=12 deg, sun_alt=27 deg.) with mlim=19.1 . There is NGC 7293 (Helix Nebula) inside IC error-box with 10^4 yrs age http://master.sai.msu.ru/static/IC/MASTERIceCube-190331A.jpg Reduction will be continued. MASTER Global Robotic Net received to socket IceCube alert 190331.29 with coordinates RA,Dec=355.6349 +71.1170 (J2000) and error-box 8.9deg. http://master.sai.msu.ru/static/IC/IC190331.29.txt and automatically inspected this localization by MASTER-Tunka, MASTER-Kislovodsk, MASTER-Tavrida http://master.sai.msu.ru/static/IC/MASTERIC190331.29map.jpg with mlim 18-20mag. If new coordinates from GCN 24028 by Kopper et al. were sent automatically to subscribers, IceCube could get follow-up in time. The message may be cited.