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GCN Circular 1602

Subject

GRB 021004: Optical Decay

Date

2002-10-07T22:35:38Z (22 years ago)

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 #1583Not found
 
 
) 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