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GCN Circular 2770

GRB 041006 (=H3570): An X-Ray Rich GRB Localized in Real Time by HETE
2004-10-06T15:09:31Z (20 years ago)
Roland Vanderspek at MIT <>
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 

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; 


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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