GCN Circular 2575
Subject
GRB040422, BVRcIc field calibration
Date
2004-04-22T21:25:25Z (20 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 shallow BVRcIc all-sky photometry for
a 11x11 arcmin field centered on the INTEGRAL coordinates
(Mereghetti et al. GCN 2572) for GRB040422
with the USNOFS 1.0-m telescope on one marginal night.
Stars brighter than V=12.5 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/grb040422.dat
The astrometry in this file is based on linear plate solutions
with respect to UCAC2. The external errors are less than 100mas.
The estimated external photometric error is about 0.03mag
and will be improved with additional calibration nights
if an afterglow is discovered.
As always, you should check the dates on the .dat file prior to
final publication to get the latest photometry. There is
a README file on the ftp directory to give you information
about the procedures used to calibrate these fields.