TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  1602
SUBJECT: GRB 021004: Optical Decay
DATE:    02/10/07 22:35:38 GMT
FROM:    Nestor Mirabal at Columbia U.  <abulafia@astro.columbia.edu>

N. Mirabal, E. K. Armstrong, J. P. Halpern (Columbia), and
J. Kemp (Joint Astronomy Centre and Columbia) report for the
MDM GRB follow-up team:

"Continued monitoring of the optical afterglow of GRB 021004 with
the MDM 1.3m yields the following measurements on 2002 Oct 7 UT:

                --------------------
                  UT      R     +/-
                --------------------
                02:38   20.19   0.03
                06:37   20.14   0.02
                11:21   20.21   0.04
                --------------------

Here we used the revised calibration of Henden (GCN #1583) in which
the reference star has R=15.52.  Although the decay appears to have
slowed over the past day, it is difficult to know at this time whether
it has stopped fading, or for how long."

An updated decay curve accounting for revised calibrations of
GCN published data is at:

http://www.astro.columbia.edu/~jules/021004.ps