TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  1978
SUBJECT: GRB030328 (=H2650): A Long, Bright GRB Localized by the HETE WXM and SXC
DATE:    03/03/28 20:31:07 GMT
FROM:    Don Lamb at U.Chicago  <lamb@oddjob.uchicago.edu>

J. Villasenor, G. Crew, R. Vanderspek, J. Doty, 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 11:20:58.34 UTC (40858.34 s UT) on 28 Mar 2003, the HETE FREGATE,
WXM, and SXC instruments detected event H2650, a long, bright GRB.

The burst triggered FREGATE in the 8-80 keV energy band; the flight
software incorrectly attributed the burst to particles, and therefore
the WXM and SXC flight localizations were not sent out.  The operations
team quickly validated the SXC flight localization and disseminated it
in a GCN Notice at 12:14:13 UT, 53 minutes after the burst.  The SXC
flight localization SNR was 6.  The SXC flight localization can be
expressed as a 90% confidence circle that is 2 arcminutes in radius and
is centered at

SXC-Flight:   RA = +12h 10m 46s, Dec = -09d 22' 29" (J2000).

Ground analysis of the WXM data and the SXC data for the burst produced
refined WXM and SXC localizations, which were reported in a GCN Notice
at 13:21:46 UT, 121 minutes after the burst.  The WXM ground
localization SNR was 25.  The WXM location can be expressed as a 90%
confidence circle that is 4.6 arcminutes in radius and is centered at

WXM-Ground:   RA = +12h 10m 53s, Dec = -09d 23' 30" (J2000).

The SXC ground localization SNR was 10.  The SXC ground localization
can be expressed as a 90% confidence circle that is 52 arcseconds in
radius and is centered at

SXC-Ground:   RA = +12h 10m 51s, Dec = -09d 21' 05" (J2000).

The burst duration t_90 in the 30-400 keV band was ~ 100 s.  The fluence
of the burst was 3.0 x 10-5 ergs cm-2 and the peak flux over 5.2 s was
7.3 x 10-7 ergs cm-2 s-1 in the same energy band.

A light curve and skymap for GRB030328 is provided at the following URL:

http://space.mit.edu/HETE/Bursts/GRB030328