[vsnet-grb-info 4896] GRB 070714A, Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6622
SUBJECT: GRB 070714A, Swift-BAT refined analysis
DATE:    07/07/14 19:38:35 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott at lheamail.gsfc.nasa.gov>

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

Using the data set from T-240 to T+962 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 070714A (trigger #284850)
(Grupe, et al., GCN Circ. 6619).  The BAT ground-calculated position is
RA, Dec = 42.933, 30.241 deg  which is
   RA(J2000)  =  2h 51m 43.8s
   Dec(J2000) = 30d 14' 28"
with an uncertainty of 1.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 96%.

The mask-weight lightcurve shows a single peak starting at T+0, peaking at
T+0.7, and ending at T+2 sec, where the rise time is a little faster than
the decay.  T90 (15-350 keV) is 2.0 +- 0.3 sec (estimated error including
systematics).

The time-averaged spectrum from T-0.7 to T+2.3 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
2.6 +- 0.2.  The fluence in the 15-150 keV band is 1.5 +- 0.2 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+0.30 sec in the 15-150 keV band
is 1.8 +- 0.2 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.

We note that the fluence ratio in a simple power-law fit between the
25-50 keV band and the 50-100 keV band is 1.52.  This fluence ratio is larger
than 1.32, which can be achieved in the Band function of alpha=-1.0, beta=-2.5,
and Epeak=30 keV.  Thus, preliminary analysis shows that Epeak of the burst
is very likely around or below 30 keV.  Therefore the burst can be classified
as an X-ray flash.