GCN Circular 16307
Subject
GRB 140512A: MASTER prompt and afterglow optical observations
Date
2014-05-19T05:47:51Z (11 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <gcncirc@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
A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik
Kislovodsk Solar Station of the Pulkovo Observatory
V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov
Blagoveschensk Educational State University, Blagoveschensk
K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk
Irkutsk State University
V.Krushinski, I.Zalozhnih, A. Popov
Ural Federal University, 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 began observations of GRB140512A (Pagani et. al. GCN
16249) from pointing on several FERMI alerts.
During the second set of observations by FERMI coordinates the GRB140512A
error box was covered by our very wide field cameras MASTER VWF
(FOV=2x384 square degrees, D=72mm, f/1.2, 1 pix = 22 arcsec) which
installed on MASTER-II telescope. So we have 5 images with 5 second
exptime without time gap since 2014-05-12 19:32:38 i.e. 29 sec. after the
trigger and 49 sec. after the burst. We did not see optical transient
(Pagani et. al. GCN 16249) at GRB140512A place. The 5-sigma upper limit
on coadd of 5 MASTER-VWF images since 49 sec. till 74 sec. after the burst
has been about 12.3 mag. The prompt images available here
http://master.sai.msu.ru/static/GRB/GRB140512A.png .
After several repointing by FERMI alerts MASTER II was pointed to the
GRB140512A 171 sec after trigger time at 2014-05-12 19:34:40.212 UT in two
polarizations by Swift coordinates. We definitely see OT on our images in
both polarizations.
Out final light curve is available in Tab. 1
Start time Exptime T-T_mid P/ eP/ P\ eP\
2014-05-12T19:34:40.212 30 186 14,45 0,04 14,37 0,03
2014-05-12T19:36:37.643 60 318 14,72 0,05 14,74 0,04
2014-05-12T19:38:24.484 60 425 15,60 0,12 15,35 0,06
2014-05-12T19:39:47.447 60 508 15,41 0,10 15,65 0,07
2014-05-12T19:41:10.651 60 591 15,75 0,13 15,75 0,08
2014-05-12T19:42:32.663 60 673 15,98 0,16 15,94 0,09
2014-05-12T19:43:54.083 60 754 16,46 0,22 16,42 0,12
2014-05-12T19:45:56.002 170 931 16,37 0,20 16,79 0,15
2014-05-12T19:50:30.564 180 1211 17,50 0,39 16,84 0,15
2014-05-12T19:56:11.667 180 1552 16,82 0,27 17,57 0,22
P/ and P\ is a polarization filter which are oriented at an angle 45 and
135 degrees to RA axis respectivel. eP/ and eP\ is a error of P/ and P\
values. T is a GRB trigger time.
The dimensionless Stokes parameter averaged over 5 first expositions is
estimated to be less than observational error which equals to 2.9% (i.e. q
= 0.3 +- 2.9%). So big error is connected to observation in a morning
twilight (sun altitude ~ 12 d) and high object zenith distance (z ~ 70 d).
Our unfiltered magnitude is well described by a parity 0.8R + 0.2B (USNO-B1)
The message may be cited.