TITLE:   GCN CIRCULAR
NUMBER:  18670
SUBJECT: GRB 151205B, Swift-BAT refined analysis
DATE:    15/12/06 17:03:30 GMT
FROM:    Hans Krimm at NASA-GSFC  <hans.a.krimm@nasa.gov>

T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC),
N. Gehrels (GSFC),H. A. Krimm (GSFC/USRA),A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), F. E. Marshall (NASA/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+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 15120B (trigger #666378)
(Marshall, et al., GCN Circ. 18659).  The BAT ground-calculated position is
RA, Dec = 41.190, -43.461 deg which is
    RA(J2000)  =  02h 44m 45.6s
    Dec(J2000) = -43d 27' 39.8"
with an uncertainty of 2.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 96%.

The mask-weighted light curve shows a single peak starting at T-2 sec
with total duration of ~5 seconds. The spacecraft slewed away from the
burst location at about T+350 seconds. T90 (15-350 keV) is 1.4 +- 0.2 sec
(estimated error including systematics).

The time-averaged spectrum from T-0.2 to T+1.3 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.74 +- 0.33.  The fluence in the 15-150 keV band is 7.7 +- 1.6 x 10^-8erg/cm2.
The 1-sec peak photon flux measured from T+0.25 sec in the 15-150 keV band
is 0.7 +- 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/666378/BA/