GRB 070721***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-239 to T+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 070721***A*** (trigger #285653)
(NAME, et al., GCN Circ. xxxx).  The BAT ground-calculated position is
RA, Dec = 3.146, -28.532 deg which is 
   RA(J2000)  =  00h 12m 35.1s 
   Dec(J2000) = -28d 31' 55.8" 
with an uncertainty of 2.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 72%.
 
[Description about the mask-weighted light curve]
T90 (15-350 keV) is 3.3 +- 0.5 sec (estimated error including systematics).
 
The time-averaged spectrum from T-0.1 to T+3.4 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
2.35 +- 0.37.  The fluence in the 15-150 keV band is 7.3 +- 1.8 x 10^-08 erg/cm2.
The 1-sec peak photon flux measured from T+0.12 sec in the 15-150 keV band
is 0.7 +- 0.1 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/285653/BA/
 
 
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## Special note (please do not include this in the email circular):
## Becuase E0 = 6.11872 is outside of the BAT energy range (15-350 keV),
## A simple power-law model is chosen despite delta chi2 > 6.
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