[vsnet-grb-info 14567] GRB 140219A: the confirmation of the brightening SDSS J102406.41+062937.6 star

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15881
SUBJECT: GRB 140219A: the confirmation of the brightening  SDSS J102406.41+062937.6 star  
DATE:    14/02/24 11:11:24 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <gcncirc at observ.inetcomm.ru>

V. Lipunov, M. Pruzhinskaya, E. Gorbovskoy, D.Denisenko, V.Kornilov, N.Tyurina, 
P.Balanutsa, A.Kuznetsov, V.V.Chazov, D.Kuvshinov
Lomonosov Moscow State University, Sternberg Astronomical Institute

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.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)

We present the reduction of the best coadded image started 2014-02-20
  14:42:07, i.e. 18.92 hour  after  trigger time with total 
exposition 3960 s (Gorbovskoy et al., GCN 15871) with  unfiltered 21.0 mag 
limit.
We  found the  optical source   inside XRT-5 error box (Mangano 
and Evans, GCN 15875) at automatic position:

T_start = 2014-02-20 14:42:07.5 (T_start-T_trig = 18.92 h)
T_mid  =  2014-02-20 16:14:23.7 (T_start-T_mid = 20.45 h)
T_fin    = 2014-02-20 17:46:40.0  (T_start-T_fin  = 22.01 h)

RA 10h 24m 06.45s
Dec +6d 29m 37.86s

(156.021889     6.420445)
with 0.7 arcsec  error.

Unfiltered magnitude:
Mag = 19.7+/-0.3 
This source coincides with SDSS J102406.41+062937.6 star.

This star must be visible at archive image of this area at the same 
telescope (MASTER II, Tunka,2011-02-06 16:34:55 180, Lipunov et all., GCN 
15879) on 4 sigma level. The absence of the SDSS J102406.41+062937.6 star 
confirms its brightening ~0.7 mag.

But the absence of the X-ray variation of XRT-5 source (P.F. Evans, 
GCN15880) argues that  brightening may be usual variable star and does not 
connect with  GRB 140219A.

All our limits published earlier are still valid (GCN 15871, GCN 15879 )

The coadded image is available at
http://observ.pereplet.ru/images/10240645+062937.jpg

The message may be cited.