TITLE:   GCN CIRCULAR
NUMBER:  23136
SUBJECT: GRB 180812A: Swift-BAT refined analysis
DATE:    18/08/12 21:19:33 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/USRA),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Sakamoto (AGU),
M. Stamatikos (OSU) (i.e. the Swift-BAT team):

Using the data set from T-240 to T+962 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 180812A (trigger #852903)
(Lien et al., GCN Circ. 23129).  The BAT ground-calculated position is
RA, Dec = 245.839, 74.674 deg which is
  RA(J2000)  =  16h 23m 21.3s
  Dec(J2000) = +74d 40' 27.0"
with an uncertainty of 2.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 26%.

The mask-weighted light curve shows a multi-peaked structure that starts
at ~T0 and ends at ~T+17 s. T90 (15-350 keV) is 16.51 +- 0.92 sec (estimated
error including systematics).

The time-averaged spectrum from T-0.30 to T+16.63 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.22 +- 0.27.  The fluence in the 15-150 keV band is 8.0 +- 1.4 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+15.62 sec in the 15-150 keV band
is 1.9 +- 0.4 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/852903/BA/