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GCN Circular 13310

Subject

GRB 120521A: Swift-BAT refined analysis

Date

2012-05-21T11:37:22Z (13 years ago)

From

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

J. R. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
M. M. Chester (PSU), E. E. Fenimore (LANL), N. Gehrels (GSFC),
H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Sakamoto (GSFC/UMBC), 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-239 to T+363 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 120521A (trigger #522578)
(Chester, et al., GCN Circ. 13302Loading...
 
 ).  The BAT ground-calculated position is
RA, Dec = 148.692, -49.422 deg, which is 
   RA(J2000)  =  09h 54m 46.1s 
   Dec(J2000) = -49d 25' 17.8" 
with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 100%.
 
The mask-weighted light curve shows FRED pulse starting at ~T+0.0, peaking
at ~T+0.1, and ending at ~T+1.0 sec.  T90 (15-350 keV) is 0.45 +- 0.08 sec
(estimated error including systematics).
 
The time-averaged spectrum from T+0.02 to T+0.56 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
0.98 +- 0.22.  The fluence in the 15-150 keV band is 7.8 +- 1.1 x 10^-8 erg/cm2.
The 1-sec peak photon flux measured from T-0.21 sec in the 15-150 keV band
is 0.9 +- 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/522578/BA/