GCN Circular 17814

GRB 150513A: Swift-BAT refined analysis

A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU),
M. Stamatikos (OSU), T. N. Ukwatta (LANL)
(i.e. the Swift-BAT team):

Using the data set from T-239 to T+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 150513A (trigger #640584) (Kocevski, et al.,
GCN Circ. 17810
Not found
 
 
).  The BAT ground-calculated position is
RA, Dec = 49.044, -22.868 deg which is
    RA(J2000)  =  03h 16m 10.6s
    Dec(J2000) = -22d 52' 03.3"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 64%.

The mask-weighted light curve shows multiple peaks with a return to background
levels in between them.  T90 (15-350 keV) is 162 +- 5 sec (estimated error
including systematics).

The time-averaged spectrum from T-54.33 to T+129.36 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.40 +- 0.07.  The fluence in the 15-150 keV band is 5.4 +- 0.2 x 10^-06 erg/cm2.
The 1-sec peak photon flux measured from T+115.41 sec in the 15-150 keV band
is 2.9 +- 0.3 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.