Skip to main content
Testing. You are viewing the public testing version of GCN. For the production version, go to
Introducing Einstein Probe, Astro Flavored Markdown, and Notices Schema v4.0.0. See news and announcements

GCN Circular 2723

XRF 040912 (=H3557): Spectral and Temporal Properties
2004-09-17T20:17:03Z (20 years ago)
Don Lamb at U.Chicago <>
XRF 040912 (=H3557):  Spectral and Temporal Properties

J-F Olive, 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, Y. Urata, 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-P Dezalay, and K. Hurley, on behalf of the HETE


The burst-average photon number spectrum of GRB 040912 is best fit by
a power-law times exponential (PLE) model with a photon index alpha =
1.75 +0.28/-0.30 and a peak energy E_peak = 14.5 +/-14.5 keV.

The fluence of the burst is (8.3 +1.4/-1.3 ) x 10-7 erg cm-2 in the 2-30
keV energy band and (3.3 +2.9/-1.7) x 10-7 erg cm-2 in the 30-400 keV
energy band.  The ratio of the fluences in the two energy bands is 2.5,
clearly making this burst an X-Ray Flash.

The T50 and T90 durations of XRF 040912 are 80 +/-5 sec and 127 +/-13
sec in the 6-40 keV energy band, and 81 +/-5 sec and 122 +/-7 sec in the
6-80 keV energy band, respectively.

This message may be cited.
Looking for U.S. government information and services? Visit