TITLE:   GCN CIRCULAR
NUMBER:  14148
SUBJECT: GRB 130122A: optical observations
DATE:    13/01/24 10:05:37 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

A. Volnova (SAI MSU/IKI), V. Linkov (ISON-Kislovodsk),  I. Molotov (KIAM), 
V. Kouprianov (GAO), A. Pozanenko (IKI),  report on behalf of larger 
collaboration:

We observed the field of  GRB 130122A (Lien  et al., GCN 14140) with 
SANTEL-400AN (0.4-m f/3)  telescope of ISON-Kislovodsk observatory. 
Observations started on  Jan. 22 (UT) 23:44  and we obtained  several 
unfiltered images  of 60 s and 100 s exposures. Initial part of our 
observations were carried under unfavorable weather conditions. Starting on 
Jan.23 (UT) 00:14:14 we clearly detect optical afterglow of GRB 130122A 
(Lien  et al., GCN 14140; Sonbas et al., GCN 14141; Gorbovskoy  et al., GCN 
14142) in single images of 60 s exposure. A  preliminary photometry of 
stacked  images is based  on USNO-B1.0 (R2)  nearby  stars:

T_start,     T0+,       Exp,     Filter,       OT
(UT)          mid (d)   (s)

00:14:14  0.00899  8x60    none      18.0 +/-0.1
00:47:45  0.04474   100     none      18.5 +/- 0.5
01:02:07  0.05579  4x60    none       >17.3