TITLE: GCN CIRCULAR NUMBER: 21132 SUBJECT: GRB 170522A: Global MASTER-Net job DATE: 17/05/23 18:17:37 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, D.Kuvshinov, A.V.Krylov, I.Gorbunov, P.Balanutsa, A.Kuznetsov, V.V.Chazov, D. Vlasenko Lomonosov Moscow State University, Sternberg Astronomical Institut of MSU K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk, O. Ershova Irkutsk State University D.Buckley, S. Potter, A.Kniazev, M.Kotze South African Astronomical Observatory R.Podesta, C.Lopez, F. Podesta Observatorio Astronomico Felix Aguilar (OAFA) , National University of San Juan, Argentina H. Levato, C. Saffe Instituto de Ciencias Astronomicas,de la Tierra y del Espacio (ICATE), San Juan, Argentina V.Yurkov, Yu.Sergienko Blagoveschensk Educational State University, Blagoveschensk A. Tlatov, V.Senik, A.V. Parhomenko, D. Dormidontov Kislovodsk Solar Station of the Pulkovo Observatory R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres The Instituto de Astrofisica de Canarias MASTER Tunka robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in Tunka was pointed to the GRB170522A 36 sec after notice time and 136 sec after trigger time at 2017-05-22 15:47:51 UT. On our first (30s exposure) set we do not OT within GBM FERMI error-box (ra=135.417 dec=27.0394 r=1.26 see Stanbro and Meegan GCN #21126 ) brighter then 16.2. Unfortunately this observation was outside of the future Fermi LAT (Arimoto and Racusin, GCN #21127) error box. Fortunatelly, we have MASTER Very Wide field cameras on all telescopes (5-10 sec exposure on 2x380 square degrees FOV) and we have images with future Fermi LAT (Arimoto and Racusin, GCN #21127) error box. There is no OT brighter ~12 mag inside the future Fermi LAT error box. The observations made on zenit distance = 66 degrees, galaxy latitude b = 40 degree. The moon (14 % bright part) below the horizon (The altitude of the Moon is -32 degree ). Observations started at twilight. The sun altitude is -15.9 degree. The area can be observed till sunrise at 2017-05-22 21:04:48 MASTER SAAO robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in SAAO was automaticaly starting survey on the FERMI GRB170522A error-box (ra=09 01 47 dec=+27 07 12 r=1 Fermi GBM error box Stanbro and Meegan GCN #21126 ) 3186 sec after notice time and 3740 sec after trigger time at 2017-05-22 16:47:55 UT. The 5-sigma upper limit on our first (60s exposure) set is about 18.7mag No OT brighter 19.5 detected in SAAO. The observations made on zenit distance = 62 degrees, galaxy latitude b = 40 degree. The moon (14 % bright part) below the horizon (The altitude of the Moon is -39 degree ). Observations started at twilight. The sun altitude is -13.9 degree. The object can be observed till sunrise at 2017-05-23 05:22:11 Unfortunately this observation was outside of the future Fermi LAT (Arimoto and Racusin, GCN #21127) error box. MASTER-OAFA robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in OAFA automaticaly was pointed to the GRB170522A 247 sec after FERMI LAT notice time (Arimoto and Racusin, GCN #21127) and 35103 sec after trigger time at 2017-05-23 01:30:38 UT . But zenit distance was very high and we received dark images. On our 4-th image (923 sec after FERMI LAT notice time (Arimoto and Racusin, GCN #21127) and 35779 sec after trigger time at 2017-05-23 01:41:54 UT.) we found 1 short optical transient within LAT error-box (ra=139.338 dec=25.67 r=0.19) brighter then 14.5 . T-Tmid Date Time Expt. Ra Dec Mag ---------|---------------------|-------|-----------------|-----------------|------- 35869 2017-05-23 01:41:54 180 ( 9h 16m 35.3s , +25d 41m 07.4s) 13.72 This object was found only on the one image. The 5-sigma upper limit has been about 14.5 mag We did not find OT brighter 18.5 on the next images. The observations made on zenit distance = 80 degrees, galaxy latitude b = 43 degree. The moon (11 % bright part) below the horizon (The altitude of the Moon is -63 degree ). The sun altitude is -50.3 degree. The object can be observed till 2017-05-23 02:44:45 . The message may be cited.