TITLE:   GCN CIRCULAR
NUMBER:  34474
SUBJECT: GRB 230816A: Swift-BAT refined analysis
DATE:    23/08/18 18:04:02 GMT
FROM:    Tyler Parsotan  at NASA GSFC <tyler.parsotan@nasa.gov>

A. Y. Lien (U Tampa), S. D. Barthelmy (GSFC),
H. A. Krimm (NSF), S. Laha (GSFC/UMBC),
C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Parsotan (GSFC/UMBC), T. Sakamoto (AGU),
M. Stamatikos (OSU) (i.e. the Swift-BAT team):


Using the data set from T-239 to T+303 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 230816A (trigger #1185673)
(Siegel, et al., GCN Circ. 34450). The BAT ground-calculated position is
RA, Dec = 328.453, 37.853 deg which is
RA(J2000) = 21h 53m 48.8s
Dec(J2000) = +37d 51' 12.1"
with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 98%.


The mask weighted light curve shows a fast rise exponential decay type single peak.
T90 (15-350 keV) is 20.48 +- 4.94 sec (estimated error including systematics).


The time-averaged spectrum from T-5.60 to T+21.08 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.43 +- 0.14. The fluence in the 15-150 keV band is 7.7 +- 0.7 x 10^-07 erg/cm2.
The 1-sec peak photon flux measured from T+0.60 sec in the 15-150 keV band
is 1.0 +- 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/1185673/BA/ <http://gcn.gsfc.nasa.gov/notices_s/1185673/BA/>