GRB 210421***A***, Swift-BAT refined analysis
 
<somebody goes first>
<add the BA alphabetically>
S. D. Barthelmy (GSFC), 
H. A. Krimm (NSF),
S. Laha (GSFC/UMBC),
A. Y. Lien (U Tampa),
C. B. Markwardt (GSFC),
D. M. Palmer (LANL),
T. Parsotan (GSFC/UMBC),
T. Sakamoto (AGU),
M. Stamatikos (OSU)
(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 210421***A*** (trigger #1044426)
(NAME, et al., GCN Circ. xxxx).  The BAT ground-calculated position is
RA, Dec = 104.883, 4.929 deg which is 
   RA(J2000)  =  06h 59m 32.0s 
   Dec(J2000) = +04d 55' 42.8" 
with an uncertainty of 1.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 44%.
 
[Description about the mask-weighted light curve]
T90 (15-350 keV) is 79.2 +- 26.8 sec (estimated error including systematics).
 
The time-averaged spectrum from T-21.7 to T+73.2 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
2.14 +- 0.13.  The fluence in the 15-150 keV band is 2.2 +- 0.2 x 10^-06 erg/cm2.
The 1-sec peak photon flux measured from T+2.47 sec in the 15-150 keV band
is 2.0 +- 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/1044426/BA/