TITLE:   GCN CIRCULAR
NUMBER:  25405
SUBJECT: GRB 190816A: Swift-BAT refined analysis
DATE:    19/08/20 00:10:43 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), H. A. Krimm (NSF),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), K. L. Page (U Leicester),
T. Sakamoto (AGU), M. Stamatikos (OSU)
(i.e. the Swift-BAT team):

Using the data set from T-862 to T+963 sec from the recent telemetry
downlink,
we report further analysis of BAT GRB 190816A (trigger #920783)
(Page et al., GCN Circ. 25368).  The BAT ground-calculated position is
RA, Dec = 341.183, -29.745 deg which is
   RA(J2000)  =  22h 44m 44.0s
   Dec(J2000) = -29d 44' 42.5"
with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 30%.

The mask-weighted light curve shows a weak multi-pulse structure that
starts at ~ T-200 s and ends at ~T+340 s. T90 (15-350 keV) is
375.0 +- 92.9 sec (estimated error including systematics).

The time-averaged spectrum from T-206.5 to T+341.6 sec is best fit by a
simple
power-law model.  The power law index of the time-averaged spectrum is
1.62 +- 0.11.  The fluence in the 15-150 keV band is 9.8 +- 0.6 x 10^-6
erg/cm2.
The 1-sec peak photon flux measured from T+151.57 sec in the 15-150 keV band
is 1.3 +- 0.3 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/920783/BA/