GCN Circular 2452

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

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, 

I. Mitrofanov, S. Charyshnikov, V. Grinkov, A. Kozyrev, M. Litvak, and
A. Sanin, on behalf of the HEND-Odyssey GRB team, and

W. Boynton, C. Fellows, K. Harshman, C. Shinohara and R. Starr, on
behalf of the GRS/Odyssey GRB team, report:

Ulysses, Mars Odyssey-HEND, and HETE (FREGATE and WXM)  observed this GRB at
40308 seconds.  Its duration was approximately 20 seconds.

As the two triangulation annuli (Ulysses/HETE and Ulysses/Odyssey) are
practically coincident, the IPN localization can best be expressed as
a single annulus centered at RA, Decl(2000)=350.299, -15.584 degrees, whose
radius is 42.882 +/- 0.076 degrees.

GRB031109 was detected by HETE as trigger H2917.  The burst was detected 
just a few seconds after the start of FREGATE and WXM operations:  it is seen
as a two-peaked burst with a hard spectrum (Epeak > 300 keV) and a 25-100 keV
fluence of 3E-6 erg/cm2.  The burst occurred well before the onset of star 
tracker operations, so the satellite aspect at the time of the trigger is
not well known:  the HETE localization is a circle of 10 degree radius centered
at RA = 21h 35m, dec = 25d 30'.

The IPN annulus intersects this circle at four points to form an error
box whose area is approximately 7900 sq. arcmin.  The intersection
points are:

     RA(2000)    DEC(2000)
     320.708      15.912
     334.747      24.605
     320.885      15.865
     334.721      24.431

A map has been posted at ssl.berkeley.edu/ipn3/031109.  HETE
lightcurves and the results of automated spectral analyses can be found
on the HETE web page http://space.mit.edu/HETE/Bursts/GRB031109a.
This error box may be improved.