GRB 160821***A***, Swift-BAT refined analysis
 
<somebody goes first>
<add the BA alphabetically>
S. D. Barthelmy (GSFC), 
J. R. Cummings (GSFC/UMBC),
N. Gehrels (GSFC),
H. A. Krimm (GSFC/USRA),
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-239 to T+400 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 160821***A*** (trigger #709357)
(NAME, et al., GCN Circ. xxxx).  The BAT ground-calculated position is
RA, Dec = 280.004, 62.387 deg which is 
   RA(J2000)  =  18h 40m 00.9s 
   Dec(J2000) = +62d 23' 13.4" 
with an uncertainty of 1.4 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 85%.
 
[Description about the mask-weighted light curve]
T90 (15-350 keV) is 0.5 +- 0.1 sec (estimated error including systematics).
 
The time-averaged spectrum from T+0.0 to T+0.5 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.88 +- 0.15.  The fluence in the 15-150 keV band is 1.2 +- 0.1 x 10^-07 erg/cm2.
The 1-sec peak photon flux measured from T-0.23 sec in the 15-150 keV band
is 1.8 +- 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/709357/BA/
 
 
############################################################################################
## Special note (please do not include this in the email circular):
## Because this is a particularly short burst (T90 < 1 sec), only the simple power-law fit
## and special SGR fit (if the burst is within 2 deg of the Galactic plane) are considered.
## That is, the cutoff power-law fit is not one of the options despite the low chi2 value.
############################################################################################