[vsnet-grb-info 20983] GRB 180805A: Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  23081
SUBJECT: GRB 180805A: Swift-BAT refined analysis
DATE:    18/08/06 01:48:56 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien at nasa.gov>

D. M. Palmer (LANL), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), P. D'Avanzo (INAF-OAB),
H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), J. P. Norris (BSU),
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+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 180805A (trigger #851829)
(D'Avanzo et al., GCN Circ. 23074).  The BAT ground-calculated position is
RA, Dec = 167.575, -45.327 deg which is
  RA(J2000)  =  11h 10m 18.1s
  Dec(J2000) = -45d 19' 35.8"
with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 64%.

The mask-weighted light curve shows a single-pulse structure that starts
at peaks at ~T0, and ends at ~T+1.9 s. T90 (15-350 keV) is 1.68 +- 0.41 sec
(estimated error including systematics).

The time-averaged spectrum from T+0.04 to T+1.90 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.58 +- 0.32.  The fluence in the 15-150 keV band is 1.1 +- 0.3 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+0.13 sec in the 15-150 keV band
is 1.1 +- 0.2 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.

Both the temporal and spectral properties of this burst lie in the
intermediate region between short and long GRBs. The lag analysis
is unavailable due to the weakness of this burst. No extended emission
is found.

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/851829/BA/