GCN Circular 2662

GRB040825B (=H3510):  An XRF Localized in Real Time by HETE

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

T. Donaghy, E. Fenimore, M. Galassi, C. Graziani, M. Matsuoka,
Y. Nakagawa, T. Sakamoto, R. Sato, Y. Shirasaki, M. Suzuki,
T. Tamagawa, T. Yamazaki, Y. Yamamoto, and A. Yoshida, on behalf of the
HETE WXM Team;

N. Butler, G. Crew, J. Doty, A. Dullighan, 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;

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

report:

At 16:21:37 UTC (58897 s UT) on 25 August 2004, the HETE FREGATE and
WXM instruments detected event GRB040825B (=H3510), a long XRF.
The burst triggered the WXM in the 2-30 keV energy band;  the burst
duration is roughly 80 seconds.  

A flight localization was automatically forwarded to the GCN 31
Not found
 
 
 seconds 
after the trigger.  The flight localization was a circle of 14' radius 
centered at 

  RA = 22h 47m 22s,   Dec = -02d 19' 05" (J2000)

Subsequent analysis of the full data set allowed the burst error region
to be reduced to a 160 sq. arcmin error box with the following coordinates, 
distributed by GCN Notice 1.8 hours after the trigger:

  RA = 22h 46m 38.9s, Dec = -02d 33m 40
  RA = 22h 46m 01.9s, Dec = -02d 29m 17s
  RA = 22h 46m 28.6s, Dec = -02d 15m 14s
  RA = 22h 47m 05.5s, Dec = -02d 19m 41s

Preliminary spectral analyses show the burst spectrum is well fit by
a cutoff powerlaw model with an Epeak of 23 keV.  The burst fluence
is 1.3e-6 erg/cm2 in the 2-30 keV band, 6.3e-7 erg/cm2 in the 30-400 
keV band;  GRB040825B is therefore an XRF.

Details of this burst can be found on the HETE web page at
  
  http://space.mit.edu/HETE/Bursts/GRB040825B.

Further observations of this source are encouraged.

This message can be cited.