GCN Circular 3189

GRB 050408 (=H3711):  A Long X-Ray-Rich GRB Detected by HETE

T. Sakamoto, G. Ricker, J-L. Atteia, N. Kawai, D. Lamb, and S. Woosley,
on behalf of the HETE Science Team;

M. Arimoto, T. Donaghy, E. Fenimore, M. Galassi, C. Graziani,
J. Kotoku, M. Maetou, M. Matsuoka, Y. Nakagawa, R. Sato, Y. Shirasaki,
M. Suzuki, T. Tamagawa, K. Tanaka, Y. Yamamoto, and A. Yoshida, on
behalf of the HETE WXM Team;

N. Butler, G. Crew, J. Doty, G. Prigozhin, R. Vanderspek,
J. Villasenor, J. G. Jernigan, A. Levine, G. Azzibrouck, J. Braga,
R. Manchanda, and G. Pizzichini, on behalf of the HETE Operations and
HETE Optical-SXC Teams;

M. Boer, J-F Olive, J-P Dezalay, and K. Hurley, on behalf of the HETE
FREGATE Team;

report:


The HETE FREGATE, WXM, and SXC instruments detected GRB 050408 (=H3711)
at 16:22:50.93 UT (58970.93 SOD) on 8 April 2005.  WXM and SXC flight
localizations were reported in a GCN Notice issued at 16:23:02, which
was 11 sec after the burst trigger and while the burst was still in
progress.

The final WXM and SXC flight localizations were reported in a GCN
Notice issued at 16:23:13 UT.  The final WXM flight localization can be
expressed as a circle of 14 arcminutes radius (90% confidence) that is
centered at

WXM-Flight:  RA = 12h 01m 55s, DEC = +10d 51' 38" (J2000).

The final SXC flight localization can be expressed as a circle of 150
arcseconds radius that is centered at

SXC-Flight:  RA = +12h 02m 15s, DEC = +10d 51' 03" (J2000).


Ground analysis produced an updated SXC localization that was reported
in a GCN Notice issued at 17:36:02.  This ground SXC localization can 
be expressed as a circle of 80 arcseconds radius that is centered at


SXC-Ground:  RA = +12h 02m 15s, DEC = +10d 52' 01" (J2000).


The burst has a duration T_90 of ~34 seconds in 7-40 keV and 7-80 keV,
and T_90 of ~15 seconds in 30-400 keV.  Preliminary spectral analyses
show the 2-30 keV fluence of GRB 050408 to be ~1.4 x 10-6 ergs cm-2 and
the 30-400 keV fluence to be ~1.9 x 10-6 ergs cm-2.  Therefore 
GRB 050408 is an "X-ray-rich" GRB.

A light curve, skymap, and spectral information for GRB 050408 are
provided at the following URL:

http://space.mit.edu/HETE/Bursts/GRB050408

This message may be cited.