GCN Circular 5180
Subject
GRB 060526: SMARTS optical/IR afterglow observations
Event
Date
2006-05-28T19:11:24Z (20 years ago)
From
Bethany Cobb at Yale U <cobb@astro.yale.edu>
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).