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 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.