TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  2443
SUBJECT: IPN triangulation of GRB031111 (=H2924): small error box
DATE:    03/11/12 22:21:25 GMT
FROM:    Kevin Hurley at UCBerkeley/SSL  <khurley@sunspot.ssl.berkeley.edu>

K. Hurley and T. Cline, on behalf of the Ulysses and HETE GRB teams,

A. von Kienlin, G. Lichti, and A. Rau, on behalf of the INTEGRAL
SPI-ACS GRB team, and

G. Ricker, J-L Atteia, N. Kawai, D. Lamb, S. Woosley, J. Doty, R.
Vanderspek, J. Villasenor, G. Crew, G. Monnelly, N. Butler, J.G.
Jernigan, A. Levine, F. Martel, E. Morgan, G. Prigozhin, J. Braga, R.
Manchanda, G.  Pizzichini, Y. Shirasaki, C. Graziani, M. Matsuoka, T.
Tamagawa, K. Torii, T. Sakamoto, A. Yoshida, E. Fenimore, M. Galassi,
T. Tavenner, T.  Donaghy, M. Boer, J-F Olive, and J-P Dezalay, on
behalf of the HETE GRB team, report:

Ulysses, INTEGRAL (SPI-ACS) and HETE (H2924: FREGATE and WXM) observed this
burst at 60313 seconds.  Its position was reported in a GCN Notice on
November 11 at 17:55:09.

As observed by Ulysses, it had a duration of approximately 10 seconds,
a 25-100 keV fluence of approximately  2.1E-06 erg/cm2, and a peak flux
of approximately  1.1E-06 erg/cm2 s over 0.50 seconds.  These numbers
are subject to more than the usual amount of uncertainty, as the
background on Ulysses was about 3 times the normal rate due to solar
protons.

We have triangulated it to a preliminary annulus centered  at RA,
Decl(2000)= 351.380, -16.219 degrees, whose radius is 86.229 +/-  0.012
degrees (3 sigma).  This intersects the WXM error box to form an
error box whose coordinates are:

     RA(2000)     DEC(2000)
      71.830      17.934
      71.792      17.969
      71.736      18.204
      71.697      18.238

The combined WXM/IPN error box area is ~24 sq. arcmin., or ~75
times smaller than the WXM-only error box.  A map has been posted
at ssl.berkeley.edu/ipn3/031111.  This error box may be 
improved.