[vsnet-grb-info 15337] GRB 140723A: MASTER optical observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  16629
SUBJECT: GRB 140723A: MASTER optical observation 
DATE:    14/07/24 13:49:03 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <gcncirc at observ.inetcomm.ru>

E. Gorbovskoy, D.Denisenko, V. Lipunov,  M.Pruzhinskaya, V.Kornilov, 
D.Kuvshinov, A.Belinski, N.Tyurina, N.Shatskiy, P.Balanutsa, D.Zimnukhov, 
A.Kuznetsov, V.V.Chazov, 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 GRB 140723A (Fermi trigger 427772193) 
48377 s (~13.4 h) after trigger time at 2014-07-23 15:02:47 UT directly 
after sunset.  Observations were made at high zenith distance (z ~ 76d) 
with the error box setting to the horizon. Therefore we have only two 
(180s exposure) successful images.

On our images we have not found optical transient within Fermi-LAT 
error-box (Bissaldi et al. GCN 16623, Burns et. al GCN 16626) and IPN 
(Hurley et al. GCN  16625, Golenetskii et. al GCN 16628) brighter than 
18.3 mag. Thus we can not confirm the LCO-Sutherland OT (Guidorzi et al. 
GCN 16627) despite ~2 hours earlier time of observations and our upper 
limit being 1 magnitude deeper than the estimated  object magnitude.

The 6x6 acrminutes MASTER-Tunka image around probable OT position (Guidorzi et 
al. GCN 16627) is available here:
http://master.sai.msu.ru/static/GRB/GRB140723_LAT.png

Our white (clear) band is well described by a parity 0.8R+0.2B (USNO B1).

The message may be cited.