[vsnet-grb-info 4294] GRB 070209, Swift-BAT refined analysis of the short hard burst

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6087
SUBJECT: GRB 070209, Swift-BAT refined analysis of the short hard burst
DATE:    07/02/09 06:31:50 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott at lheamail.gsfc.nasa.gov>

T. Sakamoto (GSFC/ORAU), 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),
A. Parsons (GSFC), G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU),
J. Tueller (GSFC)
on behalf of the Swift-BAT team:
 
Using the data set from T-240 to T+302 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 070209 (trigger #259803)
(Sato, et al., GCN Circ. 6086).  The BAT ground-calculated position is
RA, Dec = 46.213, -47.376 deg which is 
   RA(J2000)  =  03h 4m 51.2s 
   Dec(J2000) = -47d 22' 34.2" 
with an uncertainty of 2.8 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 85%.
 
The mask-weighted lightcurve has a single peak.  T90 (15-350 keV) is
0.1 +- 0.02 sec (estimated error including systematics).
 
The time-averaged spectrum from T+0.0 to T+0.1 is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.55 +- 0.39.  The fluence in the 15-150 keV band is 1.1 +- 0.3 x 10^-8
erg/cm2.  The 1-sec peak photon flux measured from T+0.00 sec in the
15-150 keV band is 2.4 +- 0.6 ph/cm2/sec.  All the quoted errors are
at the 90% confidence level.