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GCN Circular 1888

Subject
GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
Date
2003-02-26T21:35:03Z (21 years ago)
From
Don Lamb at U.Chicago <lamb@oddjob.uchicago.edu>
M. Suzuki, Y. Shirasaki, C. Graziani, M. Matsuoka, T. Tamagawa, K.
Torii, T. Sakamoto, A. Yoshida, E. Fenimore, M. Galassi, T. Tavenner,
and T. Donaghy, Y. Nakagawa, D. Takahashi, R. Satoh, and Y. Urata, on
behalf of the HETE WXM Team;

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

J. Doty, J. Villasenor, R. Vanderspek, G. Crew, G. Monnelly, N.
Butler, T. Cline, J.G. Jernigan, A. Levine, F. Martel, E. Morgan, G.
Prigozhin, 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, C.  Barraud and K. Hurley on behalf
of the HETE FREGATE Team;

write:

At 03:46:31.99 UTC (13591.99 s UT) on 26 Feb 2003, the HETE FREGATE,
WXM, and SXC instruments detected event U10893, a long GRB.  No prompt
notification was issued, because the on-board Trigger Monitor was
configured to reject triggers near the SAA.  The event was detected by
event detection software in the ground processing pipeline.

Ground analysis of the WXM data produced a localization which was
reported in a GCN Notice at 05:35:58 UT, 109 minutes after the burst.
The WXM localization SNR was 15. The WXM location can be expressed as
a 90% confidence circle that is 15 arcminutes in radius and is
centered at

WXM:   RA = +11h 33m 36s, Dec = +25d 49' 58" (J2000).

Further ground analysis of the WXM data produced a refined localization
that can be expressed as a 90% confidence circle that is 6.8 arcminutes
in radius and is centered at

WXM:   RA = +11h 33m 07.9s, Dec = +25d 51' 14.4" (J2000).

Ground analysis of the SXC data for the burst produced a more accurate
location, which was reported in a GCN Notice at 05:47:21 UT, 121
minutes after the burst. The SXC localization SNR was 5. The SXC
location can be expressed as a 90% confidence circle that is 2
arcminutes in radius and is centered at

SXC:   RA = +11h 33m 01s, Dec = +25d 53' 56" (J2000).

The SXC localization may be improved.

The burst duration in the 30-400 keV band was > 100 s. The fluence of
the burst was 5.7 x 10-6 ergs cm-2 in the 30-400 keV energy band. The
peak flux was ~1.2 x 10-7 ergs cm-2 s-1 (i.e., ~ 5 x Crab flux) in 1.2
sec in the same energy band.

A light curve and skymap for GRB030226 is provided at the following URL:

http://space.mit.edu/HETE/Bursts/U10893
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