TITLE: GCN CIRCULAR NUMBER: 18055 SUBJECT: GRB 150724A: Swift-BAT refined analysis DATE: 15/07/24 12:10:27 GMT FROM: Scott Barthelmy at NASA/GSFC D. M. Palmer (LANL), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), J. L. Racusin (NASA/GSFC), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Using the data set from T-240 to T+902 sec from recent telemetry downlinks, we report further analysis of BAT GRB 150724A (trigger #650141) (Racusin, et al., GCN Circ. 18050). The BAT ground-calculated position is RA, Dec = 97.549, -19.147 deg, which is RA(J2000) = 06h 30m 11.7s Dec(J2000) = -19d 08' 48.1" with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment). The partial coding was 48%. The mask-weighted light curve has at least 4 peaks starting at ~T-10 sec, with peaks at ~T+1 sec, ~T+24 sec, ~T+160 sec, & ~T+220 sec, and the emission ending at ~T+300 sec. T90 (15-350 keV) is 280 +- 44 sec (estimated error including systematics). The time-averaged spectrum from T-1.07 to T+325.42 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.06 +- 0.15. The fluence in the 15-150 keV band is 2.2 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+24.08 sec in the 15-150 keV band is 0.9 +- 0.2 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/650141/BA/