GCN Circular 15426
J. Gorosabel (IAA-CSIC,UPV/EHU), A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), V. Terron (IAA-CSIC) report on behalf of a larger collaboration: Further analysis of the observations of the field of GRB 131031A (Cummings GCN 15421) obtained with the 1.23m CAHA in I-band, 10.2 hr after the burst (Terron et al. GCN 15422), reveals a source consistent with the XRT afterglow candidate at the following coordinates (J2000+/-0.5"): R.A.: 01:58:26.46 Dec: -01:34:48.1 This source is not present in the archival SDSS images and has a magnitude of i(AB)=21.63+/-0.25 as compared with SDSS field stars. Thus, we propose it as the optical afterglow of GRB 131031A. Further observations will be needed to check for variability.