[vsnet-grb-info 14956] GRB 140512A: MASTER OT decay and early light curve

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  16250
SUBJECT: GRB 140512A: MASTER OT decay and early light curve
DATE:    14/05/12 20:44:05 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <gcncirc at observ.inetcomm.ru>

E. Gorbovskoy, V. Lipunov, V.Kornilov, D.Kuvshinov, A.Belinski, N.Tyurina, 
N.Shatskiy, P.Balanutsa, D.Zimnukhov, A.Kuznetsov, V.V.Chazov, D.Denisenko, 
A.Sankovich
Lomonosov Moscow State University,
Sternberg Astronomical Institute, Moscow State University

K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk
Irkutsk State University


V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov
Blagoveschensk Educational State University, Blagoveschensk

A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik
Kislovodsk Solar Station of the Pulkovo Observatory

V.Krushinsky, I.Zalozhnih,  A. Popov
Ural Federal University, Yekaterinburg, Kourovka

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)


MASTER II  robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in 
Tunka was pointed to the  GRB140512A   171 sec after trigger time at 2014-05-12 
19:34:40.212 UT in two polarizations. We definetly see OT (Pagani et. al. 
GCN 16249)  on our images in bosh polarizations.

The preliminary automatic light curve available at Tab.1 and here:
http://master.sai.msu.ru/static/GRB/GRB140512A_lc.png

Table 1. GRB140512B early automatic light curve.

        T_start         T-T_trig   mag
  2014-05-12 19:34:44.3  175 sec  13.5
  2014-05-12 19:36:36.3  287 sec  13.9
  2014-05-12 19:38:21.9  392 sec  14.5
  2014-05-12 19:39:43.7  474 sec  14.8
  2014-05-12 19:41:05.3  556 sec  15.1
  2014-05-12 19:42:26.3  637 sec  15.2
  2014-05-12 19:43:47.3  718 sec  15.5
  2014-05-12 19:45:56.8  847 sec  16.2

Our unfiltered magnitude is well described by a parity 0.8R + 0.2B 
(USNO-B1)

The power low index alpha from 175 to 847 seconds after the trigger  is
1.5 +- 0.1  (F ~ t-apha).

We erraticly reported (Ivanov et. al. GCN 16248) that we don't see object 
earlier because of the wrong identification. We are sorry for it.

The message may be cited.