[vsnet-grb-info 17490] GRB 160121A: Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  18919
SUBJECT: GRB 160121A: Swift-BAT refined analysis
DATE:    16/01/21 22:47:14 GMT
FROM:    Hans Krimm at NASA-GSFC  <hans.a.krimm at nasa.gov>

T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC),
N. Gehrels (GSFC), L. M. Z. Hagen (PSU), H. A. Krimm (GSFC/USRA),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Sakamoto (AGU), M. Stamatikos (OSU), (i.e. the Swift-BAT team):

Using the data set from T-239 to T+340 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 160121A (trigger #671231)
(Hagen, et al., GCN Circ. 18912).  The BAT ground-calculated position is
RA, Dec = 109.080, -23.590 deg which is
    RA(J2000)  =  07h 16m 19.1s
    Dec(J2000) = -23d 35' 25.5"
with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 91%.

The mask-weighted light curve shows a single peak starting at T-4 sec,
peaking at T+3 sec and returning to baseline by T+14 sec. T90 (15-350 keV)
is 12.0 +- 2.4 sec (estimated error including systematics).

The time-averaged spectrum from T-0.03 to T+14.97 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.77 +- 0.13.  The fluence in the 15-150 keV band is 6.1 +- 0.5 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+2.76 sec in the 15-150 keV band
is 1.2 +- 0.2 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/671231/BA/