HETE Burst H1896

Burst H1896 summary

  • Trigger time is
    • UTC=20020124_104115
    • GRB=GRB020124+38475
  • Triggering instrument was Fregate
  • Trigger timescale was 1.3 seconds
  • Trigger detected in 30-400 keV band

Evaluation

Real GRB, > 3 Crabs Error circle has 12 arcminute radius R.A.(J2000) = +09h 32m 49s DEC (J2000) = -11d 27m 35s


GCN Circular 1220


TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  1220
SUBJECT: GRB020124(=H1896): Localization of a Long GRB by HETE
DATE:    02/01/24 23:54:57 GMT
FROM:    George Ricker at MIT  

GRB020124(=H1896): Localization of a Long GRB by HETE

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

G. Crew, R. Vanderspek, J. Doty, G. Monnelly, J. Villasenor, N. Butler,
T. Cline, J.G. Jernigan, A. Levine, F. Martel, E. Morgan, G.
Prigozhin, J. Braga, R. Manchanda, and G. Pizzichini, on behalf of
the HETE Operations and HETE Optical-SXC Teams;

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

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

write:

At 10:41:15.15 UTC (38475.15 s UT) on 24 January, the HETE FREGATE 
and WXM instruments detected and localized a long GRB. The burst, 
H1896, was promptly reported as a GCN Alert Notice within 11 seconds 
of the detection time, but no flight localization was derived. In a 
followup GCN Notice issued 1.4 hours after the GRB, the results of an 
initial ground analysis localization were reported as an error box 
with dimensions of 26 arcmin x 27 arcmin.

Further ground analysis of the WXM data has produced a significantly 
improved location which can be expressed as a circle with a 90% 
confidence radius of 12 arc minutes centered at:

RA = +09h 32m 49s, Dec = -11d 27' 35" (J2000)

The revised error circle reported here is displaced by 9.2 arc 
minutes from the  best-fit location found in the initial HETE ground 
analysis and reported in a GCN Notice (at 24 Jan 2002 12:06:53 UT).

The burst duration in the FREGATE 8-85 keV band was ~70 s. A total of 
12,870 counts were detected during that interval, corresponding to a 
fluence of ~3 x 10-6 ergs cm-2 . The peak flux over 0.164s was >1 x 
10-7 ergs cm-2 s-1 (i.e., >3 x Crab flux). The statistical 
significance was 9 sigma in the WXM 2-25 keV band.

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