[vsnet-grb-info 3718] GRB 060908: Danish/DFOSC optical observations

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  5552
SUBJECT: GRB 060908: Danish/DFOSC optical observations
DATE:    06/09/08 14:29:17 GMT
FROM:    Evert Rol at U.Leicester  <er45 at star.le.ac.uk>

K. Wiersema (University of Amsterdam), C.C. Thoene (DARK Cosmology Centre)
and E. Rol (University of Leicester) report:

We observed the position of GRB 060908 using the Danish 1.5m telescope
equipped with DFOSC, in R band. The optical transient (Evans et al,
GCN 5544) is detected in all our exposures.

We performed photometry with respect to a nearby USNO-B1.0 star
0903-0022606, for which we assume R = 18.29.  The reported error in
our magnitude is therefore only the error in the photometry of the
transient. We find R = 21.57 +/- 0.04, 46 minutes after the trigger.

During our observations between 36 and 70 minutes after the trigger,
the optical transient is clearly decaying: a power law fit to our data
results in a decay index of 1.07 +/- 0.11. The magnitude and decay
rate suggest that the decay slowed down somewhat, after an initial
steep decline.