TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  3834
SUBJECT: GRB 050820: P60 Temporal Decay Index
DATE:    05/08/20 10:37:09 GMT
FROM:    S. Bradley Cenko at Caltech  <cenko@srl.caltech.edu>

S. Bradley Cenko (Caltech) and Derek B. Fox (Penn State) report on behalf
of a larger collaboration:

We have continued to image the afterglow (GCN 3829) of GRB 050820 (GCN
3830) with the automated Palomar 60-inch telescope.  Using the USNO-B1
star located at RA=22:29:39.88, Dec=+19:32:47.5 (USNO-B1 1095-0581263, R =
15.21) as a reference, we find, after rising to a peak magnitude of R =
14.7 approximately 7 minutes after the burst, the afterglow has exhibited
a relatively smooth power-law decay with index alpha = -0.9.  In an image
taken ~ 93 minutes after the burst, the afterglow has a magnitude of R ~
17.4.

Further observations are planned.