[vsnet-grb-info 18070] SWIFT J174540.2-290037, Swift-BAT refined analysis (trigger 689956)

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  19518
SUBJECT: SWIFT J174540.2-290037, Swift-BAT refined analysis (trigger 689956)
DATE:    16/06/10 03:55:32 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien at nasa.gov>

C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC),
N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC),
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+963 sec from the recent telemetry downlink,
we report further analysis of SWIFT J174540.2-290037 (trigger# 689956;
Barthelmy, et al., GCN Circ. 19514).  The BAT ground-calculated position is
RA, Dec = 266.408, -29.063 deg which is
  RA(J2000)  =  17h 45m 37.9s
  Dec(J2000) = -29d 03' 45.9"
with an uncertainty of 2.5 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 99%.

The mask-weighted light curve shows some weak emissions that starts
before the source came into the BAT field of view, and extends beyond the end
of the event data range. The Bayesian-block analysis failed to find the duration
due to the lack of obvious light curve structure.

The time-averaged spectrum from T+0.0 to T+944.0 sec is better-fitted by a
simple power-law model, in comparison to the cutoff power-law model. However,
with the null hypothesis probability of only ~ 0.05 for both of these models, neither
of them seem to well describe the spectrum. Using the simple power-law model,
the power law index of the time-averaged spectrum is 1.82 +- 0.16.  The fluence
in the 15-150 keV band is 3.3 +- 0.3 x 10^-6 erg/cm2. 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/689956/BA/