[vsnet-grb-info 18885] Trigger 728094, Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  20336
SUBJECT: Trigger 728094, Swift-BAT refined analysis
DATE:    16/12/24 23:58:48 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien at nasa.gov>

M. Stamatikos (OSU), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), N. Gehrels (GSFC),
H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Sakamoto (AGU), 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 trigger #728094 (Cholden-Brown, et al.,
GCN Circ. 20333).  The BAT ground-calculated position is
RA, Dec = 259.877, -25.010 deg which is
   RA(J2000)  =  17h 19m 30.5s
   Dec(J2000) = -25d 00' -37.4"
with an uncertainty of 3.2 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 12%.

The mask-weighted light curve is featureless, with a hint of some weak emission
throughout the duration when the source was in the BAT field of view from
~T-39.0 to ~T+644.0 sec. However, the very low significance (5.7 sigma)
suggests that this might be due to noise fluctuation. With the lack of afterglow
observations because of the Sun constraint, it remains difficult to determine the
source nature.

The time-averaged spectrum from T-39.0 to T+644.0 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum
is 1.70 +- 0.20.  The fluence in the 15-150 keV band is 7.5 +- 1.0 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/728094/BA/