TITLE: GCN CIRCULAR NUMBER: 2391 SUBJECT: GRB 030913, optical candidate DATE: 03/09/20 02:12:37 GMT FROM: Alberto Castro-Tirado at LAEFF-INTA GRB 030913, possible optical counterpart ---------------------------------------- S. Guziy, A. de Ugarte Postigo, A.J. Castro-Tirado, J.Gorosabel (IAA-CSIC/STScI), P. Amado, Antonio Herrería (IAA-CSIC), Pilar Ruiz-Lapuente (Univ. Barcelona), Javier Méndez (ING, La Palma), J. M. Castro Cerón (STScI), and A. Zurita (ING, La Palma) report: "On Sep 18.04 UT (4.25 days after the burst) we imaged 80% of the HETE-II error box for GRB 030913 (Suzuki et al., GCNC 2383) with WHT at La Palma trough Johnson V filter. We detected an uncatalogued point like source of 20.9 +/- 0.1 at the following coordinates +/- 2": RA(J2000) = 20:58:46.5 DEC(J2000)= -02:20:59 On Sept 19.87 UT we imaged again the same field from the 1.5m telescope at Sierra Nevada Observatory (OSN, Granada) and detected an object at V mag = 23.6 +/- 0.5 on an equivalent position. Images of the field are posted on: http://www.iaa.es/~deugarte/GRBs/GRB030913/ Further images in R and B bands have been obtained that confirm the detection. Other observations are encouraged to confirm the relation of this object with GRB030913" This message may be quoted.