[vsnet-grb-info 3210] GRB060501: Super-LOTIS observations

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  5045
SUBJECT: GRB060501: Super-LOTIS observations
DATE:    06/05/01 20:22:13 GMT
FROM:    Peter A. Milne at Super-LOTIS  <pmilne at as.arizona.edu>

P.A.Milne (Steward Obs) reports on behalf of the Super-LOTIS GRB team:

We observed the location of the BAT error circle of the GRB 060501,
as reported in GCN 5040 (Swift trigger 208050; La Parola et
al.,) using the 60cm Super-LOTIS telescope at Kitt Peak, Arizona.
Imaging began at 09:30:30 UT, 1.25 hours after the burst, and consisted
of three series of one-minute exposures in the R filter (12, 23 & 17
images per series, respectively). Seeing was typically 2.7".

A source is detected at the positionreported by Fox and Cenko (GCN 5044) 
in all three summed images created from the individual exposures. 
Using 8 stars from the USNO-B1 catalog, a
single image produced from the first two series led to the following
magnitudes for the suggested counterpart, R1=18.39 +/- 0.11,
R2=18.54 +/- 0.12. However, these magnitudes are very close to the
magnitude of the star 1339-0447675, which is listed at a position
consistent with the optical counterpart position listed by Fox and Cenko.
 
We therefore suggest that the optical counterpart candidate reported
in GCN 5044 is instead star 1339-0447675 from the USNO-B1.0 catalog.

Analysis of the last series of exposures is on-going.