[vsnet-grb-info 13276] GRB 130508A, Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  14613
SUBJECT: GRB 130508A, Swift-BAT refined analysis
DATE:    13/05/09 10:46:07 GMT
FROM:    Jay R. Cummings at NASA/GSFC/Swift  <james.r.cummings at nasa.gov>

T. Sakamoto (AGU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC),
S. T. Holland (STScI), H. A. Krimm (GSFC/USRA), A. Y. Lien (NASA/GSFC/ORAU),
C. B. Markwardt (GSFC), D. M. Palmer (LANL), G. Sato (ISAS), M. Stamatikos (OSU),
J. Tueller (GSFC), T. N. Ukwatta (MSU)
(i.e. the Swift-BAT team):
  
Using the data set from T-60 to T+243 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 130508A (trigger #555413) (Holland, et al.,
GCN Circ. 14607).
The BAT ground-calculated position is RA, Dec = 305.351, 34.966 deg which is
    RA(J2000)  =  20h 21m 24.2s
    Dec(J2000) = +34d 57' 57.6"
with an uncertainty of 2.2 arcmin, (radius, sys+stat, 90% containment).  The
partial coding was 60%.
  
The mask-weighted light curve shows a single peak from about T+9 to T+55 sec.
T90 (15-350 keV) is 42 +- 11 sec (estimated error including systematics).
  
The time-averaged spectrum from T+9.62 to T+56.75 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.80 +- 0.23.  The fluence in the 15-150 keV band is 6.6 +- 1.0 x 10^-07 erg/cm2.
The 1-sec peak photon flux measured from T+11.07 sec in the 15-150 keV band
is 0.7 +- 0.2 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/555413/BA/