GCN Circular 7591

G. Sato (GSFC/ISAS), S. D. Barthelmy (GSFC), W. Baumgartner (GSFC/UMBC),
J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC),
H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), F. E. Marshall (GSFC),
K. McLean (GSFC/UMD), D. Palmer (LANL), T. Sakamoto (GSFC/UMBC),
M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. Ukwatta (GWU)
(i.e. the Swift-BAT team):
 
Using the data set from T-187 to T+723 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 080411 (trigger #309010)
(Marshall, et al., GCN Circ. 7584
Not found
 
 
).  The BAT ground-calculated position is
RA, Dec = 37.961, -71.297 deg, which is 
   RA(J2000)  =  02h 31m 50.6s 
   Dec(J2000) = -71d 17' 49.6" 
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 86%.
 
The mask-weighted light curve shows two clusters of overlapping peaks.
The first starts at T+0.0 sec and rises to a peak in 1 sec.  The second peak
is at T+7 sec; the third at T+10 sec, and the 4th at T+19 sec at 25 cnt/cm2/sec
(15-150 keV).  The lightcurve returns to background before the beginning
of the second cluster of peaks.  The 5th peak starts at ~T+39 sec,
rises linearly, peaking at ~T+41 src at 43 cnts/cm2/sec.  There are two more
much smaller peaks at T+55 and T+64 sec.  The lightcurve returns to background
by ~T+95 sec.  There is a gap in the downlinked data from T+300 to T+420 sec.
It appears that the burst has returned to background well before this gap,
but should later downlinks show on-going activity, we will issue an updated
circular.  T90 (15-350 keV) is 56 +- 1 sec (estimated error including
systematics).
 
The time-averaged spectrum from T-0.0 to T+84.3 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.75 +- 0.03.  The fluence in the 15-150 keV band is 2.64 +- 0.01 x 10^-5 erg/cm2.
The 1-sec peak photon flux measured from T+40.45 sec in the 15-150 keV band
is 43.2 +- 0.9 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/309010/BA/