[vsnet-grb-info 18941] GRB 170112A: Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  20443
SUBJECT: GRB 170112A: Swift-BAT refined analysis
DATE:    17/01/12 23:33:12 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien at nasa.gov>

A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), N. Gehrels (GSFC),
H. A. Krimm (NSF/USRA), C. B. Markwardt (GSFC),
J. P. Norris (BSU), 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-240 to T+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 170112A (trigger #732188)
(Mingo, et al., GCN Circ. 20436).  The BAT ground-calculated position is
RA, Dec = 15.232, -17.233 deg which is
   RA(J2000)  =  01h 00m 55.7s
   Dec(J2000) = -17d 13' 57.9"
with an uncertainty of 2.5 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 100%.

The mask-weighted light curve shows a single-peaked structure that starts
and peaks at ~T0, and ends at ~T+0.06 s. T90 (15-350 keV) is 0.06 +- 0.02 sec
(estimated error including systematics).

The time-averaged spectrum from T-0.00 to T+0.06 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.17 +- 0.34.  The fluence in the 15-150 keV band is 1.3 +- 0.4 x 10^-8 erg/cm2.
The 1-sec peak photon flux measured from T-0.47 sec in the 15-150 keV band
is 0.3 +- 0.1 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.

Using a 16-ms binned light curve, the lag analysis finds a lag of 19 (-17, +36) ms for
the 100-350 keV to 25-50 keV, -7 (-12, +14) ms for the 50-100 keV to 15-25 keV
band, and 0 (-7, +7) ms for the 50-100 keV to 25-50 keV. These values are
consistent with those of a short GRB. Moreover, no extended emission are found.

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/732188/BA/