{
  "bibcode": "2008GCN..8452....1C",
  "body": "B. E. Cobb (UC Berkeley) reports:\n\nUsing the ANDICAM instrument on the 1.3m telescope at CTIO, we obtained \noptical/IR imaging of the error region of GRB 081029 (GCN 8435, Sakamoto \net al.) at three epochs with mid-exposure times of 2008-10-29 04:18 UT \n(2.57 hrs post-burst), 04:50 UT (3.10 hrs post-burst) and 05:21 UT (3.62 \npost-burst).  At each epoch, several dithered images were obtained in each \nfilter, with total summed exposure times of 180s in each of BRIJK and 120s \nin each of H and V.\n\nThe GRB afterglow (e.g. GCN 8436, Rykoff et al. and GCN 8437, Clemens et \nal.) is detected in all our filters:\n\nfilter  2.57 hrs\t3.10 hrs\t3.62 hrs\nB       19.69+/-0.04 \t19.85+/-0.04   \t20.00+/-0.05\nV       18.26+/-0.03  \t18.38+/-0.03   \t18.57+/-0.04\nR       17.32+/-0.02  \t17.50+/-0.02   \t17.66+/-0.02\nI       16.79+/-0.03   \t16.94+/-0.03   \t17.15+/-0.03\nJ       15.83+/-0.08   \t16.02+/-0.08   \t16.03+/-0.08\nH       15.00+/-0.08   \t15.13+/-0.08   \t15.32+/-0.08\nK       14.25+/-0.08  \t14.35+/-0.08   \t14.60+/-0.08\n\nThese preliminary magnitudes are calibrated using Landolt standard stars \nin the optical and 2MASS stars in the IR.\n\nBetween 2.57 hrs and 3.62 hours post-burst, the afterglow decays with an \napproximate optical decay rate of alpha~-0.9 (where afterglow flux\nis proportional to t^alpha).",
  "circularId": 8452,
  "createdOn": 1225322388000,
  "email": "bcobb@astro.berkeley.edu",
  "subject": "GRB 081029, SMARTS optical/IR afterglow observations",
  "submitter": "Bethany Cobb at UC Berkeley  <bcobb@astro.berkeley.edu>",
  "eventId": "GRB 081029"
}