GCN Circular 998
Subject
GRB010222: Optical observation and decay
Date
2001-03-01T09:21:10Z (24 years ago)
From
Christian Veillet at CFHT <veillet@cfht.hawaii.edu>
The optical counterpart of GRB010222 has been observed using the
CFHT Multi Object Spectrograph in imaging mode at the Cassegrain
focus of the 3.6-m CFH Telescope on the night of Feb. 27 to 28.
One image was obtained in relatively poor conditions (seeing ~ 1.5").
A preliminary reduction using stars (223.008250,43.006507) and
(223.098277,42.994077) from Henden's list (GCN #987) gives:
Feb. 28.653 UTC R = 22.60 +/- 0.15
The relative photometry of the two stars used is consistent
with our image within 0.02 magnitudes. Using all the measurements
of the R magnitude of the OT published in the GCN's (corrected if
needed to put them back in the photometric system of Henden's list),
the R magnitude is following a nice power law decay with an index of
1.20 +/- 0.07 since 0.6 days after the burst.
An image of the OT and a graph of the decay are available at
http://www.cfht.hawaii.edu/~veillet/grb.html
S. Lilly and J. McDonald are acknowledged for their help in
this observation.
This message may be cited.
--
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Dr. Christian Veillet, CFHT Senior Resident Astronomer
Phone: (808) 885-3161 http://www.cfht.hawaii.edu/~veillet/
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