[vsnet-grb-info 2248] GRB051008: optical candidate

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4087
SUBJECT: GRB051008: optical candidate
DATE:    05/10/11 19:26:24 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen at iki.rssi.ru>

V.Rumyantsev (CrAO), V.Biryukov (SAI, MSU), A.Pozanenko (IKI), M. Ibrahimov
(MAO)  on behalf of larger GRB follow up collaboration report:

We reanalyzed the R-band observations of GRB051008  with 2.6m Shajn
telescope of CrAO  (Rumyantsev et al., GCN4081).  Within  XRT  error circle
(Perri et al., GCN4073) we found two objects. One object #1 was reported
early in GCN 4081:

RA(J2000) =13 31 29.98
Dec       =+42 05 52.06

It is clearly visible in both epochs of observation.  Object  #2  is apart
6.5" S-W from the  object  #1, and  is not visible in second epoch. The
photometry against of USNO A2.0 (R) is following:

Mid time     Exposure    object#1        object#2
Oct.8 (UT)
 17:14        15x60 s     21.50+/-0.13    22.19+/-0.27
 17:37        22x60 s     21.32+/-0.13   >22.6 (3 sigma UL)

We suggest object #2 as an afterglow candidate.
The temporal index estimated from our observations is alpha < -0.5.

Image of  the first epoch can be found at
http://grb.rssi.ru/GRB051008/GRB051008_ZTSh_R1.gif

[Correction to GCN 4081: The start of observation on Oct. 8 is 17:05:08
(UT), i.e 32 minutes after the burst onset.]

This message can be cited.