TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5180 SUBJECT: GRB 060526: SMARTS optical/IR afterglow observations DATE: 06/05/28 19:11:24 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 060526 (GCN 5162, Campana et al.) with a mid-exposure time of 2006-05-27 01:13 UT (~8.7 hours post-burst) and again at 2006-05-27 04:07 UT (~11.6 hours post-burst). Total summed exposure times for each observation amounted to 36 minutes in I and 30 minutes in J. The afterglow of GRB 060526 is visible in each combine image. The preliminary magnitudes reported below were calibrated using several USNO-B1.0 stars in the I-band and two 2MASS standards in J. [The errors on the photometric calibration are ~0.2 in I and ~0.02 in J; these errors are in addition to the statistical errors listed below.] time post-burst I magnitude J magnitude ------------------------------------------------------ 8.7 hours 18.99 +/- 0.02 18.16 +/- 0.06 11.6 hours 19.31 +/- 0.02 18.58 +/- 0.07 The afterglow decay index is constrained by our observations to be alpha = 1.2 +/- 0.2 from 8.7 to 11.6 hours post-burst. This value is in agreement with the decay value from 5 to 16 hours post-burst reported by Khamitov et al. (GCN 5173) and Halpern et al. (GCN 5176).