[vsnet-grb-info 13857] GRB 130903A: ISON-Kislovodsk optical Upper Limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15171
SUBJECT: GRB 130903A: ISON-Kislovodsk optical Upper Limits
DATE:    13/09/03 13:21:41 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen at iki.rssi.ru>

A. Volnova (IKI),  V. Nevskiy (ISON),  I. Molotov (KIAM), A. Pozanenko 
(IKI),  report on  behalf of larger collaboration:

We observed the field of GRB 130903A (INTEGRAL trigger 6930; Mereghetti et 
al. 2013, GCN 15169)  with SANTEL-400AN (0.4-m f/3)  telescope of 
ISON-Kislovodsk observatory.Observations started on  Sep. 09 (UT) 01:11:40, 
i.e. 34 minutes after burst triger.   We obtained  several unfiltered images 
of 100 s exposure. We do not detect any source within 1.5 arcmin of error 
circle localization (Mereghetti et al. 2013, GCN 15169) .  Photometry of 
combined image is following

T_start,                     T0+,       Exp.,   Filter,  UL (3 sigma)
(UT)                          mid (d)    (s)

01:11:40T01:11:40      0.02363  1000    none     >19.6

and based on  SDSS  stars, R (gri -> R  transformations by Lupton 2005):

#   SDSS                      R        Err_R
1  J052835.34-000624.7 15.543 0.013
2  J052817.12-000749.0 14.650 0.012
3  J052841.64-000642.3 14.233 0.013

 Within error circle (Mereghetti et al. 2013, GCN 15169) we note a presence 
of  probable bright galaxy  J052830.20-000723.9 r=19.706
(however marked in SDSS-DR9 as point like object).