TITLE:   GCN CIRCULAR
NUMBER:  12620
SUBJECT: GRB 111204A, Swift-BAT refined analysis
DATE:    11/12/04 23:02:55 GMT
FROM:    Tilan Ukwatta at GSFC/GWU  <tilan.ukwatta@gmail.com>

C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC),
E. E. Fenimore (LANL), N. Gehrels (GSFC),
H. A. Krimm (GSFC/USRA), D. M. Palmer (LANL), A. M. Parsons (GSFC),
T. Sakamoto (GSFC/UMBC), G. Sato (ISAS),
E. Sonbas (GSFC/USRA/Adiyaman Univ.), M. Stamatikos (OSU),
J. Tueller (GSFC), T. N. Ukwatta (GWU)
(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 111204A (trigger #509018) (Sonbas, et al., GCN Circ. 12612).
The BAT ground-calculated position is RA, Dec = 336.651, -31.414 deg
which is
   RA(J2000)  =  22h 26m 36.2s
   Dec(J2000) = -31d 24' 49.4"
with an uncertainty of 2.2 arcmin, (radius, sys+stat, 90%
containment). The partial coding was 75%.

The mask-weighted light curve shows two peaks. Initial peak starts
at the trigger time and last until ~T+10 sec. The second broad peak
starts at ~T+43 sec, peaks at ~T+48 sec, and ends at ~T+90 sec.
T90 (15-350 keV) is 48.0 +/- 22.6 sec (estimated error including
systematics).

The time-averaged spectrum from T+33.0 to T+81.0 sec is best fit by a
simple power-law model.  The power law index of the time-averaged
spectrum is 1.83 +/- 0.30.  The fluence in the 15-150 keV band is
4.7 +/- 0.9 x 10^-07 erg/cm2. The 1-sec peak photon flux measured
from T+56.50 sec in the 15-150 keV band is 0.3 +/- 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/509018/BA/