GCN Circular 2770

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

T. Donaghy, E. Fenimore, 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-F Olive, J-P Dezalay, and K. Hurley, on behalf 
of the HETE FREGATE Team; 

report:

The HETE Fregate and WXM instruments detected GRB 041006 (=H3570) at 
12:18:08 UT (44288 SOD) on 06 October 2004.  The WXM flight software 
localized the burst in real time, resulting in a GCN Notice 42 seconds 
after the burst trigger.  The flight error region was a circle of 
14 arcminutes radius (90% confidence) centered at

  RA = 00h 54m 54s, DEC = +01d 18' 37" (J2000).

Ground analyses of the burst data allow the error region to be refined
to a circle of 5.0 arcminutes radius (90% confidence) centered at

  RA = 00h 54m 53s, DEC = +01d 12' 04" (J2000).

Preliminary spectral analyses show the 2-30 keV fluence of GRB 041006 to
be 5e-6 erg/cm2 and the 30-400 keV fluence to be 7e-6 erg/cm2:  the
classification for GRB 041006 is, therefore, "X-ray rich GRB".  

GRB 041006 is very similar to GRB 030329 in its lightcurve shape and 
spectral characteristics, although it is 20x fainter than GRB 030329.
GRB 041006 shows a soft precursor before the main gamma-ray pulse.  The 
empirical redshift indicator for this burst is 0.4; for GRB 030329, it 
was 0.2.

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