H. A. Krimm (GSFC/USRA), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), A. Rowlinson (U Leicester), T. Sakamoto (GSFC/UMBC),
M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU)
(i.e. the Swift-BAT team):
Using the data set from T-240 to T+302 sec from the recent telemetry downlink,
we report further analysis of event from SGR 1E 1841-045 (trigger #455904)
(Rowlinson, et al., GCN Circ. 12079). The BAT ground-calculated position is
RA, Dec = 280.329, -4.934 deg, which is
RA(J2000) = 18h 41m 19.0s
Dec(J2000) = -04d 56' 00.9"
with an uncertainty of 1.5 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 18%.
The mask-weighted light curve shows a single spike that starts at ~T_zero
and ends at ~T+0.04 sec. T90 (15-350 keV) is 0.020 +- 0.009 sec
(estimated error including systematics).
The time-averaged spectrum from T-0.0 to T+0.1 sec is best fit by a power law
with an exponential cutoff. This fit gives a photon index 0.04 +- 0.91,
and Epeak of 32.8 +- 4.7 keV (chi squared 43.0 for 56 d.o.f.). For this
model the total fluence in the 15-150 keV band is 1.6 +- 0.2 x 10^-7 erg/cm2
and the 1-sec peak flux measured from T-0.43 sec in the 15-150 keV band is
3.6 +- 0.5 ph/cm2/sec. A fit to a simple power law gives a photon index
of 2.68 +- 0.15 (chi squared 85.2 for 57 d.o.f.). All the quoted errors
are at the 90% confidence level.
The results of the batgrbproduct analysis are available at