TITLE:   GCN CIRCULAR
NUMBER:  14123
SUBJECT: GRB 121229A, Swift-BAT refined analysis
DATE:    12/12/30 02:33:05 GMT
FROM:    Hans Krimm at NASA-GSFC  <hans.a.krimm@nasa.gov>

H. A. Krimm (GSFC/USRA),S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC),J. R. Cummings (GSFC/UMBC),
N. Gehrels (GSFC),C. B. Markwardt (GSFC),D. M. Palmer (LANL),
T. Sakamoto (AGU), E. Sonbas (NASA/GSFC/Adiyaman Univ.),
M. Stamatikos (OSU),J. Tueller (GSFC),T. N. Ukwatta (MSU)
(i.e. the Swift-BAT team):

Using the data set from T-60 to T+243 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 121229A (trigger #544347)
(Sonbas, et al., GCN Circ. 14115).  The BAT ground-calculated position is
RA, Dec = 190.095, -50.588 deg which is
    RA(J2000)  =  12h 40m 22.7s
    Dec(J2000) = -50d 35' 16.9"
with an uncertainty of 2.8 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 39%.  The mask-weighted light curve shows a broad
structure beginning at least at T-60 seconds and lasting until T+60 sec.
Since there is no data from before the start of the burst, T90 cannot be
accurately calculated at this time.  It is approximately 100 seconds.

The time-averaged spectrum from T+0.00 to T+64.00 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
2.43 +- 0.46.  The fluence in the 15-150 keV band is 4.6 +- 1.3 x 10^-7erg/cm2.
The 1-sec peak photon flux measured from T+0.00 sec in the 15-150 keV band
is 0.1 +- 0.0 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/544347/BA/