[vsnet-grb-info 14239] GRB 131125A: MASTER-Net very early optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15553
SUBJECT: GRB 131125A: MASTER-Net very early optical observations
DATE:    13/11/29 18:47:14 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <gcncirc at observ.inetcomm.ru>

Gorbovskoy, V. Lipunov,D.Denisenko, V.Kornilov, D.Kuvshinov,  N.Tyurina,
N.Shatskiy, P.Balanutsa, D.Zimnukhov, A.Kuznetsov, V.V.Chazov, 
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 Kislovodsk was pointed to the  GRB131125A 10 s after notice 
time and 24 sec after GRB time at 2013-11-25 16:33:25 UT.
But IPN  error box (GCN 15546) was outside of FOV of our MASTER-II 
telescope and very wide field camera (usually we follow up all Fermi 
alerts).

After first coordinates specification we cover IPN error box using very 
wide field cameras. The first images covered  error-box was obtained 49 
sec after GRB time at 2013-11-25 16:33:40 UT.
The 5-sigma upper limit has been about 12 mag on single 5 seconds exposure 
images and 13.5 on coadd of first 14 consecutive images
The 5-sigma upper limit has been about 14.1 mag
We find several optical marginal candidates to OT.

Name        R.A.           Dec.      m
MASTER_1  114.775649     46.120371   13.6
MASTER_2  114.597740     48.927898   13.7
MASTER_3  114.835195     47.047021   13.0

One sigma coordinate error is +- 7 arcsec.

The first image available here:
http://master.sai.msu.ru/static/GRB/GRB131125_first.jpeg

The coadd images here:
http://master.sai.msu.ru/static/GRB/GRB131125_coadd.jpeg

The message may be cited.