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GCN Circular 1997

Subject
GRB030329 (=H2652): A Long, Extremely Bright GRB Localized by the HETE WXM and SXC
Date
2003-03-29T19:53:03Z (21 years ago)
From
Don Lamb at U.Chicago <lamb@oddjob.uchicago.edu>
R. Vanderspek, G. Crew, J. Doty, J. Villasenor, 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;

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

T. Donaghy, M. Suzuki, Y. Shirasaki, C. Graziani, M. Matsuoka, T.
Tamagawa, K. Torii, T. Sakamoto, A. Yoshida, E. Fenimore, M. Galassi,
T. Tavenner, Y. Nakagawa, D. Takahashi, R. Satoh, and Y. Urata, on
behalf of the HETE WXM Team;

M. Boer, J-F Olive, J-P Dezalay, C.  Barraud and K. Hurley on behalf
of the HETE FREGATE Team;

write:

At 11:37:14.67 UTC (41834.67 s UT) on 29 Mar 2003, the HETE FREGATE,
WXM, and SXC instruments detected event H2652, a long, extremely
bright GRB.

The burst triggered FREGATE in the 6-120 keV energy band.  The burst
occurred outside of the effective FOV of the WXM Y-camera.  Ground
analysis of the SXC data produced a localization that was reported in a
GCN Notice at 12:50:24 UT, 73 minutes after the burst.  The SXC ground
localization SNR was 20.  Further ground analysis of the SXC data has
provided an SXC localization that can be expressed as a 90% confidence
circle that is 2 arcminutes in radius and is centered at

SXC-Ground:   RA = +10h 44m 50s, Dec = +21d 30' 54" (J2000).

The SXC localization is dominated by systematic errors, which are
larger than usual because the burst occurred at the edge of the SXC
FOV.  (The error circle radius of 2 arcminutes reported in the GCN
Notice for H2652 did not include the larger systematic errors.)

Ground analysis of the WXM data produced a WXM localization.  The WXM
ground localization SNR is > 20.  The WXM localization can be expressed
as a 90% confidence rectangle that is 12 arcminutes in width and 2.25
degrees in length.  The center of the rectangle lies at

WXM-Ground:   RA = +10h 44m 24.7, Dec = +23d 20' 20" (J2000),

and its corners lie at

RA = +10h 44m 39.6s, Dec = +23d 29' 20",
RA = +10h 43m 53.5s, Dec = +23d 26' 35",
RA = +10h 44m 09.8s, Dec = +21d 11' 38",
RA = +10h 44m 55.9s, Dec = +21d 14' 17" (J2000).

The width of the WXM localization is dominated by systematic errors,
which are larger than usual because the burst occurred at the edge of
the WXM FOV.  The WXM localization is a long, narrow strip because the
burst occurred at the edge of the WXM FOV in a region of the sky that
would have been viewed by the YB-camera, which is not operational.

The burst duration in the 30-400 keV band was > 25 s. The fluence  of
the burst was ~1 x 10-4 ergs cm-2 and the peak flux over 1.2 s was > 7
x 10-6 ergs cm-2 s-1 (i.e., > 100 x Crab flux) in the same energy band.

A light curve and skymap for GRB030329 is provided at the following URL:

http://space.mit.edu/HETE/Bursts/GRB030329

[GCN OPS NOTE (29mar03): The "...on 28 Mar 2003,..." in the first line
was corrected to "...on 29 Mar 2003,...".]
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