[vsnet-grb-info 20809] GRB 180705A: Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22907
SUBJECT: GRB 180705A: Swift-BAT refined analysis
DATE:    18/07/06 03:32:53 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien at nasa.gov>

D. M. Palmer (LANL), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), H. A. Krimm (NSF/USRA),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
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 180705A (trigger #846299)
(Stamatikos et al., GCN Circ. 22902).  The BAT ground-calculated position is
RA, Dec = 212.605, -11.640 deg which is
  RA(J2000)  =  14h 10m 25.1s
  Dec(J2000) = -11d 38' 23.7"
with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 36%.

The mask-weighted light curve shows some weak emission that starts at ~T0 and
ends at ~T+130 s. However, the burst went out of the BAT FOV from T+158 s to
T+204 s due to a preplanned slew, and thus there might be additional
emission when the burst was out of the FOV. The burst came back in the BAT FOV
shortly during the slew period (from T0+205 s to T0+262 s), though no emission
are found during this time. T90 (15-350 keV) is 123.2 +- 16.6 sec (estimated
error including systematics).

The time-averaged spectrum from T+0.26 to T+133.70 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.63 +- 0.22.  The fluence in the 15-150 keV band is 2.0 +- 0.3 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+3.60 sec in the 15-150 keV band
is 0.7 +- 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/846299/BA/