TITLE: GCN CIRCULAR NUMBER: 7591 SUBJECT: GRB 080411, Swift-BAT refined analysis DATE: 08/04/12 14:32:04 GMT FROM: Scott Barthelmy at NASA/GSFC 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). 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/