TITLE: GCN CIRCULAR NUMBER: 16699 SUBJECT: GRB 140817A: Swift-BAT refined analysis DATE: 14/08/17 17:16:02 GMT FROM: Jay R. Cummings at NASA/GSFC/Swift J. R. Cummings, S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (NASA/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), 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+962 sec from the recent telemetry downlink, we report further analysis of BAT GRB 140817A (trigger #609736) (Sbarufatti, et al., GCN Circ. 16695). The BAT ground-calculated position is RA, Dec = 127.244, 58.191 deg which is RA(J2000) = 08h 28m 58.5s Dec(J2000) = +58d 11' 27.0" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 75%. The mask-weighted light curve shows multiple sharp peaks from T-20 to T+12 seconds, then a return to background levels until about T+170 seconds where 2 overlapping FRED peaks begin, lasting until about T+250 seconds. T90 (15-350 keV) is 244 +- 13 sec (estimated error including systematics). The time-averaged spectrum from T-21.26 to T+270.27 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.48 +- 0.08. The fluence in the 15-150 keV band is 4.6 +- 0.2 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from T+2.64 sec in the 15-150 keV band is 7.2 +- 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/609736/BA/