//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26920 SUBJECT: Fermi-LAT ANTARES 200127.79 coincidence: MASTER alert observation and presence of young pulsar close to error-box DATE: 20/01/28 21:11:53 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, N.Tyurina, E. Gorbovskoy, O.Gress, V.Kornilov, P.Balanutsa,A.Kuznetsov, V. Vladimirov, D. Vlasenko, F.Balakin, I.Gorbunov, D.Zimnukhov, V.Senik, T.Pogrosheva, D. Kuvshinov, V.Shumkov (Lomonosov Moscow State University, SAI, Physics Department), D. Buckley(South African Astronomical Observatory), R. Rebolo, M. Serra(The Instituto de Astrofisica de Canarias), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), 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), O.A. Gres, N.M. Budnev, O.Ershova (Irkutsk State University, API), V. Yurkov, A. Gabovich, Yu. Sergienko(Blagoveschensk Educational State University) MASTER Global Robotic Net (http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy,v. 2010, 30L) started inspect observations of ANTARES alert 200127.79 (Fermi-LAT ANTARES GCN 26915) 13h after trigger time with mlim=20.0 by MASTER-OAFA. Observations started when Error-box_center_Altitude was 40deg, Dist. to Moon: 92deg, Moon disk: 0.1. Error box Gal. latitude: -0.620347 Gal. longitude: 329.684389 We also have ~400 images of this error-box made by MASTER-SAAO very wide field cameras (MASTER-VWFC 384square degrees) started ~7h after trigger time during MASTER LIGO/Virgo S200128d alert observation (Lipunov et al. GCN 26903, LVC GCN 26906 ). We note this error-box is near MW - no galaxies, Blazars/QSO. There are 2 pulsars 1) at thederror box border PSR J1601-5244 J1601-5244 in 0.237deg. ( usual 2 sec pulsar, not interesting) 2) Young PSR J1601-5335 (288 ms period) in 0.638 deg from the center of error-box with 73300 years old. This is may be interesting as possible source of high energy particles. High energy neutriutrino can be result of interaction particle accelerated by SN shell or pulsar with shell. Optical observations and analysis proceed. This message may be cited.