GRB 241218***A***, Swift-BAT refined analysis
 
<somebody goes first>
<add the BA alphabetically>
S. D. Barthelmy (GSFC), 
R. Gupta (GSFC),
H. A. Krimm (NSF),
S. Laha (GSFC/UMBC),
A. Y. Lien (U Tampa),
C. B. Markwardt (GSFC),
M. J. Moss (GSFC),
D. M. Palmer (LANL),
T. Parsotan (GSFC),
D. Sadaula (GSFC/UMBC),
T. Sakamoto (AGU)
(i.e. the Swift-BAT team):
 
Using the data set from T-520 to T+962 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 241218***A*** (trigger #1275005)
(NAME, et al., GCN Circ. xxxx).  The BAT ground-calculated position is
RA, Dec = 185.686, 29.986 deg which is 
   RA(J2000)  =  12h 22m 44.7s 
   Dec(J2000) = +29d 59' 09.1" 
with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 52%.
 
[Description about the mask-weighted light curve]
T90 (15-350 keV) is 23.4 +- 4.5 sec (estimated error including systematics).
 
The time-averaged spectrum from T-1.8 to T+26.2 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.32 +- 0.26.  The fluence in the 15-150 keV band is 5.5 +- 1.0 x 10^-07 erg/cm2.
The 1-sec peak photon flux measured from T+8.89 sec in the 15-150 keV band
is 0.6 +- 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/1275005/BA/