GCN Circular 958

E. Berger (Caltech), D. A. Frail (NRAO), P. A. Price , J. S. Bloom, T. J.
Galama (Caltech), R. Kudritzki (IFA), and F. Bresolin (ESO) report on
behalf of a larger collaboration:

"Beginning on February 22.21 UT we observed the entire BeppoSAX error
circle of GRB010220 (GCN#953
Loading...
 
 ) with the VLA at 4.86 and 8.46 GHz.  Inside
this region we detect one weak source (6.5 sigma), which is not cataloged
in the NRAO VLA Sky Survey (NVSS), at RA=02:36:52.1, DEC=61:43:49.1, with
a conservative error of 0.3" in each.  The detected source is clearly seen
in the 4.86 GHz image, but it is only marginally detected at 8.46 GHz (~ 4
sigma). We also detect several sources which correspond to cataloged NVSS
sources.  We note that the uncataloged source is at the detection
threshold of NVSS.  Further observations at the VLA are planned.

In addition, R. Kudritzki and F. Bresolin obtained a single I- (100 s) and
R-band (300 s) exposure using the Low-Resolution Imaging Spectrometer
(LRIS; Oke et al. 1995) on both nights (21.313 and 22.293 Feb 2001 UT).
Using ~200 tie stars from the USNO A2.0 catalogue, an astrometric plate
solution was obtained for the Keck images.  No object is present at either
epoch and either filter at the position of the radio source.  There is a
very bright star ~12 arcsec to the southwest of the radio position.  We
preliminarily estimate the 3-sigma upper-limit to be R ~ 23.5 mag using an
unsaturated star common to the USNO-A2.0 and the R-band image of the
second night.  Given the proximity to the Galactic plane, infrared
observations are encouraged."

This message may be cited.