GRB 090418***A***, Swift-BAT refined analysis
 
<somebody goes first>
<add the BA alphabetically>
S. D. Barthelmy (GSFC), 
W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC),
N. Gehrels (GSFC),
H. A. Krimm (GSFC/USRA),
A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC),
D. M. Palmer (LANL),
T. Sakamoto (AGU),
M. Stamatikos (OSU),
T. N. Ukwatta (LANL)
(i.e. the Swift-BAT team):
 
Using the data set from T-240 to T+962 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 090418***A*** (trigger #349510)
(NAME, et al., GCN Circ. xxxx).  The BAT ground-calculated position is
RA, Dec = 269.323, 33.402 deg which is 
   RA(J2000)  =  17h 57m 17.6s 
   Dec(J2000) = +33d 24' 06.8" 
with an uncertainty of 1.4 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 31%.
 
[Description about the mask-weighted light curve]
T90 (15-350 keV) is 56.3 +- 4.1 sec (estimated error including systematics).
 
The time-averaged spectrum from T-8.3 to T+61.1 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.34 +- 0.07.  The fluence in the 15-150 keV band is 4.7 +- 0.2 x 10^-06 erg/cm2.
The 1-sec peak photon flux measured from T+0.06 sec in the 15-150 keV band
is 1.9 +- 0.3 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/349510/BA/