TITLE: GCN CIRCULAR NUMBER: 10670 SUBJECT: GRB 100424A, Swift-BAT refined analysis DATE: 10/04/24 23:50:55 GMT FROM: Jay R. Cummings at NASA/GSFC/Swift H. A. Krimm (GSFC/USRA), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), E. A. Hoversten (PSU), C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL), A. M. Parsons (GSFC), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. N. Ukwatta (GWU) (i.e. the Swift-BAT team): Using the data set from T-60 to T+243 sec from the recent telemetry downlink, we report further analysis of BAT GRB 100424A (trigger #420367) (Hoversten et al., GCN Circ. 10667). The BAT ground-calculated position is RA, Dec = 209.453, 1.512 deg which is RA(J2000) = 13h 57m 48.6s Dec(J2000) = +01d 30' 44.2" with an uncertainty of 1.5 arcmin, (radius, sys+stat, 90% containment). The partial coding was 88%. The mask-weighted lightcurve shows a single broad peak from about T+20 to T+150 sec. T90 (15-350 keV) is 104 +- 15.5 sec (estimated error including systematics). The time-averaged spectrum from T+22.3 to T+148.5 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.83 +- 0.13. The fluence in the 15-150 keV band is 1.5 +- 0.1 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from T+58.28 sec in the 15-150 keV band is 0.4 +- 0.1 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/420367/BA/