TITLE:   GCN CIRCULAR
NUMBER:  484
SUBJECT: Refined IPN localization of GRB991216
DATE:    99/12/18 05:34:16 GMT
FROM:    Kevin Hurley at UCBerkeley/SSL  <khurley@sunspot.ssl.berkeley.edu>

K. Hurley, on behalf of the Ulysses GRB team, and M. Feroci,
on behalf of the BeppoSAX GRB team, report:

We have obtained a refined IPN annulus for GRB991216, approximately
two times narrower than the one reported in the automated GCN/IPN/
Huntsville localization circulated earlier today.  The annulus center
is at RA(2000), Decl.(2000) = 346.505, +31.230, and the radius is
84.915 +/- 0.016 degrees (3 sigma).  The annulus reduces the area of
the RXTE error box reported in the GCN/RXTE_PCA burst position notice
circulated earlier today, and its center line passes approximately
3 arcseconds from the optical transient position reported by
Halpern et al. (GCN 472).   This annulus can be refined further.

Due to hacker activity, a map cannot be posted immediately on
the IPN website.  Contact khurley@sunspot.ssl.berkeley.edu for
one.