[vsnet-grb-info 13802] GRB 130822A, Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15116
SUBJECT: GRB 130822A, Swift-BAT refined analysis
DATE:    13/08/23 01:23:49 GMT
FROM:    Jay R. Cummings at NASA/GSFC/Swift  <james.r.cummings at nasa.gov>

T. N. Ukwatta (MSU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC),
D. Kocevski (NASA/GSFC/ORAU), H. A. Krimm (GSFC/USRA),
A. Y. Lien (NASA/GSFC/ORAU), C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Sakamoto (AGU), G. Sato (ISAS), M. Stamatikos (OSU), J. Tueller (GSFC),
(i.e. the Swift-BAT team):
  
Using the data set from T-60 to T+123 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 130822A (trigger #567163)
(Kocevski, et al., GCN Circ. 15112).  The BAT ground-calculated position is
RA, Dec = 27.931, -3.193 deg which is
    RA(J2000)  =  01h 51m 43.4s
    Dec(J2000) = -03d 11' 34.0"
with an uncertainty of 2.5 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 92%.
  
The mask-weighted light curve shows a single peak.  T90 (15-350 keV) is
0.04 +- 0.01 sec (estimated error including systematics).
  
The time-averaged spectrum from T-0.004 to T+0.044 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.64 +- 0.29.  The fluence in the 15-150 keV band is 1.3 +- 0.3 x 10^-08 erg/cm2.
The 1-sec peak photon flux measured from T-0.48 sec in the 15-150 keV band is
0.3 +- 0.1 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/567163/BA/