L. Barbier (GSFC), S. D. Barthelmy (GSFC), J. Cummings (GSFC/UMBC),
E. Fenimore (LANL), N. Gehrels (GSFC), H. Krimm (GSFC/USRA),
C. Markwardt (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC),
T. Sakamoto (GSFC/ORAU), G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU),
M.C. Stroh (PSU), J. Tueller (GSFC), T. Ukwatta (GWU)
(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 070611 (trigger #282003)
(Stroh et al., GCN Circ. 6494). The BAT ground-calculated position is
RA, Dec = 2.003, -29.758 deg which is
RA(J2000) = 0h 8m 0.8s
Dec(J2000) = -29d 45' 28"
with an uncertainty of 1.8 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 50%.
The BAT light curve shows a single, symmetric peak. T90 (15-350 keV)
is 12.0 +- 1 sec (estimated error including systematics). There is a
possible second episode of emission ( at ~4.5 sigma) starting at T+70
and lasting for ~15 sec.
The time-averaged spectrum from T-6.3 to T+7.3 sec is best fit by a
simple power-law model. The power law index of the time-averaged
spectrum is 1.66 +- 0.22. The fluence in the 15-150 keV band is
3.9 +- 0.6 x 10^-07 erg/cm2. The 1-sec peak photon flux measured
from T+2.76 sec in the 15-150 keV band is 0.8 +- 0.2 ph/cm2/sec.
All the quoted errors are at the 90% confidence level.