TITLE:   GCN CIRCULAR
NUMBER:  16316
SUBJECT: GRB 140521A: Swift-BAT refined analysis
DATE:    14/05/22 13:27:00 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC),
N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (NASA/UMBC),
C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU),
M. Stamatikos (OSU), E. Troja (NASA/GSFC/UMCP), J. Tueller (GSFC), T. N. Ukwatta (MSU)
(i.e. the Swift-BAT team):
 
Using the data set from T-240 to T+963 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 140521A (trigger #599546)
(Troja, et al., GCN Circ. 16311).  The BAT ground-calculated position is
RA, Dec = 320.177, 67.587 deg, which is 
   RA(J2000)  =  21h 20m 42.6s 
   Dec(J2000) = +67d 35' 12.7" 
with an uncertainty of 1.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 55%.
 
The mask-weighted light curve shows a single peak starting at ~T-2 sec,
peaking at ~T+1 sec, and ending at ~T+11 sec with a tail out to ~T+50 sec.
T90 (15-350 keV) is 9.88 +- 1.09 sec (estimated error including systematics).
 
The time-averaged spectrum from T+0.15 to T+11.44 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.42 +- 0.11.  The fluence in the 15-150 keV band is 9.5 +- 0.6 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+0.64 sec in the 15-150 keV band
is 1.9 +- 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/599546/BA/