TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4175 SUBJECT: GRB051028: WHT optical candidate DATE: 05/10/29 05:34:42 GMT FROM: Martin Jelinek at Inst.Astrophys.Andalucia,Granada M. Jelinek, S.B.Pandey, S.S.Guziy, A.J.Castro-Tirado, J. Gorosabel, A. de Ugarte Postigo, and S. Vitek (IAA CSIC Granada, Spain) and J.T.A. De Jong, (Max Planck Intitut fuer Astronomie, Heidelberg, Germany) report We have observed the complete errorbox of HETE trigger 3951 (Hurley et al, GCN 4172) with the prime focus camera of William Herschel Telescope at La Palma starting 21:42UT (ie. ~7h after the GRB). We detect an object within the XRT errorbox (Racusin et al, GCN 4174) at coordinates RA 01:48:15.01 Dec 47:45:09.2 (+/- 1.0", J2000), with a rough magnitude R=22, which is not present in DSS. Further observations will be needed to confirm whether this is indeed the optical afrterglow of GRB051028. The image limit is ~24.2. This message may be cited.