[vsnet-grb-info 14300] GRB 131225A: MASTER-Net optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15614
SUBJECT: GRB 131225A: MASTER-Net optical observations
DATE:    13/12/26 16:29:15 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <gcncirc at observ.inetcomm.ru>

E. Gorbovskoy, D.Denisenko, V. Lipunov, V.Kornilov, D.Kuvshinov, 
A.Belinski, N.Tyurina, N.Shatskiy, P.Balanutsa, D.Zimnukhov, A.Kuznetsov,
V.V.Chazov, A.Sankovich
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 Kislovodsk was pointed to the  GRB131225A 6 hours after trigger 
time at 2013-12-25 15:53:40 UT.
We cover full MAXI error box (A. Kawagoe et al GCN 15609) using MASTER II 
twin telescope in parallel mode with FOV 4 sq. degrees.
Observations were made in the extremely  rich field (with galactic 
latitude b=-4 deg).
The  5-sigma upper limit has been about 19.0 mag on our first (180s 
exposure) image. On coadd of first 19 images with total exposure 3420 sec 
and middle time 2013-12-25 16:30:25 UT the  5-sigma upper limit has been 
20.5 mag.

Inside MAXI field of view we have detected two objects not present in
USNO-B1.0 catalog with the following coordinates and unfiltered
magnitudes:

ID #1191735: 06 19 43.71 +04 47 37.6  (20.13m)
ID #1191736: 06 17 51.08 +04 57 19.8  (20.26m)

We have identified both objects with the red stars on the digitized
Palomar IR plates, as well as in WISE and UKIDSS catalogs.

WISE J061943.55+044738.8 (W1=14.33 W2=14.14)
UGPS J061943.55+044739.1 (J=15.42 H=14.88 K=14.47)

WISE J061751.09+045719.6 (W1=15.79 W2=15.46)
UGPS J061751.05+045719.7 (J=18.24 H=17.40 K=17.17)

Also, in error box we found 2 known minor planets (Groom and 2004 OZ). The 
total number of known asteroids in our FOV is 11. There is no new minor 
planet found in error box.

The combined optical image is available here
http://master.sai.msu.ru/static/GRB/GRB131225A_MAXI/GRB131225A.jpeg

The message may be cited.