TITLE: GCN CIRCULAR NUMBER: 16500 SUBJECT: GRB 140629A: MASTER-Net preliminary light curve DATE: 14/07/01 15:21:21 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs E. Gorbovskoy (Lomonosov Moscow University) V. Krushinski (Ural Federal State University) M. Pruzhinskaya (Lomonosov Moscow University) P.Balanutsa, A.Kuznetsov, V.V.Chazov, N.Tyurina, D.Denisenko Lomonosov Moscow State University, Sternberg Astronomical Institute, Moscow State University V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov, A. Gabovich Blagoveschensk Educational State University, Blagoveschensk K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk Irkutsk State University I.Zalozhnih, A. Popov Ural Federal University, Kourovka A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory Hugo Levato and Carlos Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE) Claudio Mallamaci, Carlos Lopez and Federico Podest Observatorio Astronomico Felix Aguilar (OAFA) Three MASTER system telescopes located in Blagoveshchensk, Tunka and Kislovodsk have observed GRB140629A (Lien et al., GCN 16477) from 33 seconds till ~9 hours after the trigger. MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in Blagoveschensk was pointed to GRB140629A 15 sec after notice time and 33 sec after trigger time at 2014-06-29 14:18:03.188 UT and found OT in SWIFT error-box. MASTER II Tunka was pointed to GRB140629A 78 sec after trigger time at 2014-06-29 14:18:48.102 UT on the evening twilight sky (Sun ~5 d. below horizon) with dark sky observations starting ~ 50 min after trigger time. MASTER II Kislovodsk was pointed to GRB140629A ~3.2 hours after the trigger directly after the Sun set and weather conditions became suitable. The preliminary light curve is available here: http://master.sai.msu.ru/static/GRB/GRB140629A_slope2.png The optical transient (Lien et al., GCN 16477; Yurkov et al., GCN 16478; Moskvitin et al., GCN 16489; Bikmaev et al., GCN 16482; Masi, GCN 16483; Maehara, GCN 16484; Malesani et al., GCN 16485; Sonbas et al., GCN 16486 etc.) has a maximum at ~ 150 sec. after the burst, reaching 13.8 mag, after which it shows a power law decay. The power law index (alpha) from 200 to 10000 seconds after the trigger is 1.12 +- 0.1 (F ~ t^-alpha). There was no polarization more than 3% discovered on afterglow stage.