[vsnet-grb-info 4936] GRB 070724, Swift-BAT refined analysis of a short burst

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6656
SUBJECT: GRB 070724, Swift-BAT refined analysis of a short burst
DATE:    07/07/24 15:31:04 GMT
FROM:    Ann M. Parsons at NASA/GSFC/Swift  <parsons at milkyway.gsfc.nasa.gov>

A. Parsons (GSFC), L. Barbier (GSFC), S.D. Barthelmy (GSFC),
J. Cummings (GSFC/UMBC), E. Fenimore (LANL),
N. Gehrels (GSFC), H. Krimm (GSFC/USRA),
C. Markwardt (GSFC/UMD), D. Palmer (LANL),
T. Sakamoto (GSFC/ORAU), G. Sato (GSFC/ISAS),
M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC),
T. Ukwatta (GWU), H. Ziaeepour (UCL-MSSL)
(i.e. the Swift-BAT team):

Using the data set from T-310 to T+ 310 sec from the recent
telemetry downlink, we report further analysis of BAT GRB 070724
(trigger #285948) (Ziaeepour, et al., GCN Circ. 6654).  The BAT
ground-calculated position is RA, Dec = 27.824, -18.610 deg which is
    RA(J2000) = 1h 51m 17.9s
    Dec(J2000) = -18d 36' 35"
with an uncertainty of 2.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 91%.

The mask-weighted light curve for GRB 070724 consists of a single spike
peaking at  T+0.2 sec.  Upon inspection of the mask weighted light curve
out to T + 310 sec we find no evidence for extended emission.
T90 (15-350 keV) is 0.4 +- 0.04 sec (estimated error including
systematics).

The time-averaged spectrum from T-0.0 to T+0.4 sec is best fit by
a simple power-law model. The power law index of the time-averaged
spectrum is 1.81 +- 0.33. The fluence in the 15-150 keV band is
3.0 +- 0.7 x 10^-08 erg/cm2. The 1-sec peak photon flux measured
from T-0.30 sec in the 15-150 keV band is 1.0 +- 0.2 ph/cm2/sec.
All the quoted errors are at the 90% confidence level.