TITLE:   GCN CIRCULAR
NUMBER:  16381
SUBJECT: GRB 140610A: MASTER  optical observations
DATE:    14/06/11 13:19:03 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <gcncirc@observ.inetcomm.ru>

E. Gorbovskoy, V. Lipunov, M.Pruzhinskaya,  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 Kislovodsk was pointed to the  GRB140610A   16931 sec (~4.7 h) 
after trigger time at 2014-06-10 21:13:41 UT directly after weather 
conditions became satisfactory. On our first single and coadd images  we 
haven`t found optical transient  within Swift error-box (Evans et. al. GCN 
16375).
The 5-sigma unfiltgred upper limit has been about:


T_start             Exptime  dT[s]  Limit  Coadd
2014-06-10 21:13:41   180 s  17021  17.8    1
2014-06-10 21:13:41   540 s  17241  18.3    3
2014-06-10 21:13:41  3600 s  19079  18.5   20
2014-06-10 21:13:41 2x3600 s 19079  18.7   40*

* Coadd of images taken from two parallel tubes.
dT is middle time of exposition (dT = T_middle - T_trigger)
Our white (clear) band is well described by a parity 0.8R+0.2B (USNO B1).
The very high extinction E(B-V) ~ 2.6 Óomplicates the analysis.

The message may be cited.