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GCN Circular 456

GRB991208, optical observations
1999-12-12T17:52:41Z (24 years ago)
Peter Garnavich at Center for Astrophysics <>
Peter Garnavich (CfA/Notre Dame) and
Alberto Noriega-Crespo (IPAC/CalTech)

We imaged the field of GRB991208 with the Vatican Advanced Technology
Telescope (VATT) on 1999 Dec 12.52 (UT) in an R filter.  The optical
afterglow (GCN 452 & 453) was detected in 3x600s exposures and using a single
set of Landolt standards we estimate the R-band brightness to be 20.5+/-0.1
mag.  This is consistent with the brightness predicted by Jensen et al.
(GCN 454) for the steeper of their two suggested decay rates, that
is a decay index of -2.15.  A bright star 43" West and 24" South of the
optical transient is estimated to have R=15.9+/-0.1.

[GCN OPS NOTE:  This circular was delayed in distribution by 2 hours
due to the use of a different account domain than by prior arrangement.]

[GCN ED NOTE (12Dec99):  The line "...afterglow (GCN 453) was detected"
was changed to "...afterglow (GCN 452 & 453) was detected".]
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