GCN Circular 4116

A. Yoshida, 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,
N. Ishikawa, A. Kobayashi, J. Kotoku, M. Maetou, M. Matsuoka,
Y. Nakagawa, T. Sakamoto, R. Sato, T. Shimokawabe, Y. Shirasaki,
S. Sugita, M. Suzuki, T. Tamagawa, and K. Tanaka, 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 051021
(=H3947) at 13:21:57 UT (48117 SOD) on 21 October 2005.  The
WXM flight localization was first reported in a GCN Notice issued 
at 13:22:11 UT, which was 14s after the burst trigger.

Ground analysis of the WXM data produced a refined WXM localization that
was issued in a GCN Notice at 14:25:34 UT.  This ground WXM localization
can be expressed as a circle of 7.5 arcminutes radius (90% confidence),
centered at

  R.A. = 01h 56m 24s ; Dec. = +09d 07' 05" (J2000).

The SXC detected this event in its Y camera. Ground analysis of the SXC
data therefore produced a 1-dimensional location.  The intersection of
this location with the WXM ground location was issued in a GCN Notice at
14:59:49 UT.  This location can be expressed as a box with corners:

 R.A. = 01h 56m 01.92s ; Dec. = +09d 02' 02.4"
 R.A. = 01h 56m 54.00s ; Dec. = +09d 05' 16.4"
 R.A. = 01h 56m 54.72s ; Dec. = +09d 07' 22.8"
 R.A. = 01h 59m 57.12s ; Dec. = +09d 03' 46.8" (J2000).

Further analysis is in progress.