TITLE:   GCN CIRCULAR
NUMBER:  21112
SUBJECT: GRB 170519A: Swift-BAT refined analysis
DATE:    17/05/19 15:26:19 GMT
FROM:    Hans Krimm at NSF/NASA-GSFC  <hkrimm@nsf.gov>

H. A. Krimm (NSF/USRA), S. D. Barthelmy (GSFC),  J. R. Cummings (CPI),
A. Y. Lien (GSFC/UMBC), 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-240 to T+630 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 170519A (trigger #753445)
(Ukwatta, et al., GCN Circ. 21106).  The BAT ground-calculated position is
RA, Dec = 163.429, 25.374 deg which is 
  RA(J2000)  =  10h 53m 42.9s 
  Dec(J2000) = +25d 22' 26.6" 
with an uncertainty of 1.5 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 100%.

The mask-weighted light curve shows an initial peak starting around T-30 s, peaking
at T+0 s, and decaying by T+15 s.  Then there is a second, weaker peak from about
T+180 s to T+220 s. T90 (15-350 keV) is 216.4 +- 49.4 sec (estimated error including 
systematics).

The time-averaged spectrum from T-28.5 to T+255.6 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.94 +- 0.26.  The fluence in the 15-150 keV band is 1.1 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+0.84 sec in the 15-150 keV band
is 0.7 +- 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/753445/BA/