GCN Circular 1302
Subject
GRB020305 BVRI field photometry
Date
2002-03-23T18:41:04Z (23 years ago)
From
Arne A. Henden at USNO/USRA <aah@nofs.navy.mil>
A. Henden (USRA/USNO) reports on behalf of the USNO GRB team:
We have acquired BVRcIc all-sky photometry for
an 11x11 arcmin field in the error box for GRB020305
(Ricker et al. GCN 1262; Hurley et al. GCN 1263)
with the USNOFS 1.0-m telescope on one marginally photometric
night. The field is approximately centered on
the position of the candiate optical transient reported
by Price et al. (GCN 1267). Stars brighter than
V=13.5 are saturated and should be used with care.
We have placed the photometric data on our anonymous ftp site:
ftp://ftp.nofs.navy.mil/pub/outgoing/aah/grb/grb020305.dat
The conditions were basically clear, but early evening clouds
prevented field acquisition until it was near airmass 2.0.
For that reason, there is a slight possibility that the
photometry has larger than the expected 0.02mag external
error, but all tests (such as color consistency) seem reasonable.
The astrometry in this file is based on linear plate solutions
with respect to USNO-A2.0. The internal errors are less than 100mas.
Note that the source mentioned in GCN 1267 is near the northwestern
edge of the error circle, and so the current field photometry does
not do a good job of calibrating small-field images centered on
the error circle. We intend to take another shallower dataset
in the near future centered at the HETE coordinates.