TITLE: GCN CIRCULAR NUMBER: 7024 SUBJECT: GRB 071031, SMARTS afterglow observations DATE: 07/10/31 03:21:10 GMT FROM: Bethany Cobb at Yale U B. E. Cobb (Yale), part of the larger SMARTS consortium, reports: Using the ANDICAM instrument on the 1.3m telescope at CTIO, we obtained optical/IR imaging of the error region of GRB 071031 (GCN 7020, Stroh et al.), with a mid-exposure time of 2007-10-31 01:46 UT, which is ~40 minutes post-burst. Several dithered images were obtained in each filter, with total summed exposure times of 180s in each of BRIYJK and 120s in each of H and V. The GRB afterglow (GCN 7020, Stroh et al. & GCN 7021, Kruehler et al.) is detected at I=17.4+/-0.1 (Photometry is calibrated against USNO-B1.0 stars). Additional imaging at 1.5 hours post-burst indicates an approximate decay rate of alpha~-0.6 (where afterglow flux is proportional to t^alpha). [GCN OPS NOTE(31oct07): Per author's request, the "071030" was changed to "071031".]