TITLE: GCN CIRCULAR NUMBER: 8323 SUBJECT: GRB 081003A: OSN optical observations DATE: 08/10/04 06:08:03 GMT FROM: Alberto Castro-Tirado at Inst.de Astro. de Andalucia A. de Ugarte Postigo (ESO, Santiago), F. J. Aceituno, M. Jelínek, J. Gorosabel and A.J. Castro-Tirado (IAA-CSIC, Granada) on behalf of a larger collaboration report: "We have observed the field of GRB 081003A detected by INTEGRAL (Mereghetti et al. GCN 8314) with the 1.5m OSN telescope at Sierra Nevada Observatory (Granada, Spain). The observations consisted of 6x300s in I-band, 2x300s in R-band and 2x300s in V-band (5.07, 6.17 and 5.31h after the burst trigger respectively). We do not detect any new optical source within the Swift/XRT error box (Page et al. GCN 8319) down to 3-sigma limiting magnitudes of I > 22.0 and R > 22.5. We note, however that there could be a marginal object (with low S/N significance in the I-band frame) at coordinates (J2000): R.A.: 17:29:33.85, Dec.: +16:34:14.1 (+/-0.7"), consistent with the XRT error box. Deeper observations would be needed in order to confirm the reality of this source."