GCN Circular 983
Subject
GRB010222: fading behavior
Date
2001-02-24T03:39:15Z (23 years ago)
From
Krzysztof Z. Stanek at CfA <kstanek@cfa.harvard.edu>
K. Z. Stanek, P. Challis, S. Jha, R. Kilgard, J. McDowell
(Harvard-Smithsonian CfA) and P. M. Garnavich (Notre Dame) report:
We have obtained additional R-band data for the optical afterglow of
the GRB010222 using the F. L. Whipple Observatory 1.2m telescope:
HJD-2450000 UT R_c exp
1963.9457 010223 10:48 20.16+-0.07 600 sec
Combined with our earlier R-band data (GCN 970), this indicates a
power-law decay with a slope of 0.89, consistent with previous
determinations (GCNs 973, 975).
In the B-band, between 4.3 hours and 24.2 hours after the burst the
afterglow dimmed by about 1.8 magnitudes:
HJD-2450000 UT B exp
1962.9855 010222 11:46 18.46+-0.02 600 sec
1963.8173 010223 07:43 20.25+-0.10 600 sec
This is consistent with no color evolution between B and R.
Errors in the magnitudes are statistical only. The B-band magnitudes
are relative to star "A" as marked in the finding chart at
http://cfa-www.harvard.edu/cfa/oir/Research/GRB/, assuming its
magnitude B=17.6.
Reductions of additional data are under way.
This message can be cited.