[vsnet-grb-info 8147] GRB 090715A: Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9680
SUBJECT: GRB 090715A: Swift-BAT refined analysis
DATE:    09/07/16 13:24:23 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott at lheamail.gsfc.nasa.gov>

W. H. Baumgartner (GSFC/UMBC), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC),
E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL), A. M. Parsons (GSFC),
J. L. Racusin (PSU), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS),
M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
 
Using the data set from T-239 to T+963 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 090715A (trigger #357498)
(Racusin, et al., GCN Circ. 9666).  The BAT ground-calculated position is
RA, Dec = 152.102, 10.006 deg, which is 
   RA(J2000)  =  10h 08m 24.5s 
   Dec(J2000) = +10d 00' 22.4" 
with an uncertainty of 2.4 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 22%.
 
The mask-weighted light curve shows a single spike starting at ~T-0.1 sec,
peaking at ~T+0.1 sec, and ending at ~T+0.7 sec.  Following the intial spike,
there is extended emission from ~T+20 to ~T+55 sec at a flux level ~50 times
lower than the peak flux of the spike.  T90 (15-350 keV) is 63 +- 18 sec
(estimated error including systematics).
 
The time-averaged spectrum from T-0.1 to T+67.8 sec is best fit by a simple
power-law model.  We note that this spectral analysis includes both
the spike and the extended emission.  Qualitatively, the spike is harder
than the extended emission. The power law index of the time-averaged spectrum is
1.28 +- 0.42.  The fluence in the 15-150 keV band is 9.8 +- 2.2 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T-0.11 sec in the 15-150 keV band
is 3.9 +- 0.5 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level. 
 
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/357498/BA/