GCN Circular 598
Subject
GRB000301c - R photometry and nearby faint source confirmation
Date
2000-03-07T22:57:59Z (24 years ago)
From
Christian Veillet at CFHT <veillet@cfht.hawaii.edu>
The candidate for the optical transient (OT) associated with the gamma ray burst
GRB000301c has been observed in imaging mode with MOS on the 3.6-m CFH Telescope
in the course of the French GRB follow-up program at CFHT (M. Boer, CESR,
C. Veillet, CFHT).
The OT has the following magnitude, using star A (GCN573) photometry (GCN583):
R = 21.70 +/- 0.07 2000 March 7.65 (UTC)
This value does not fit very well with the the R magnitudes published in the
previous GCN, in particular by Mohan(595), if we assume a power law common
to all observations. In fact, the best fit of the data published so far is
obtained with a linear magnitude decay of 0.32 +/- 0.02 mg/day...
The acceleration in the decay in K (GCN596) seems also to be seen in R.
More data, as well as a careful reanalysis of the existing images, are
clearly needed!
The faint source found on March 5 (GCN592), recognized in GCN594 as identical
to the one detected in IR at NASA IRTF, is definitely there also
on the March 7 image. A composite of the two images is available at
http://www.cfht.hawaii.edu/~veillet/grb.html .
Its R magnitude is measured as 24.3 +/- 0.3 , to be refined with further
analysis.
S. Lilly is acknowledged for his 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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