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GCN Circular 11866

Subject

GRB 110402A: Swift-BAT refined analysis

Date

2011-04-02T13:59:12Z (13 years ago)

From

Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>

M. Stamatikos (OSU), 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 (GSFC/UMBC),
J. Tueller (GSFC), T. N. Ukwatta (MSU)
(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 110402A (trigger #450545)
(Ukwatta, et al., GCN Circ. 11857Not found
 
 
).  The BAT ground-calculated position is
RA, Dec = 197.432, 61.247 deg, which is 
   RA(J2000)  =  13h 09m 43.7s 
   Dec(J2000) = +61d 14' 49.6" 
with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 10%.
 
The mask-weighted light curve shows 5 spikes (each with a duration less than 0.5 sec)
with the first at ~T+1.5 sec and the last at ~T+6 sec.  These are followed
by softer emission out to ~T+90 sec.  T90 (15-350 keV) is 60.9 +- 6.9 sec
(estimated error including systematics).
 
The time-averaged spectrum from T-0.4 to T+69.7 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.59 +- 0.17.  The fluence in the 15-150 keV band is 3.4 +- 0.4 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+3.18 sec in the 15-150 keV band
is 4.1 +- 0.7 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/450545/BA/