TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3667 SUBJECT: GRB050724: Refined analysis of the Swift-BAT possible short burst DATE: 05/07/24 16:27:35 GMT FROM: Scott Barthelmy at NASA/GSFC H. Krimm (GSFC/USRA), L. Barbier (GSFC), S. Barthelmy (GSFC), J. Cummings (GSFC/NRC), E. Fenimore (LANL), N. Gehrels (GSFC), D. Hinshaw (GSFC-SPSYS), D. Hullinger (GSFC/UMD), C. Markwardt (GSFC/UMD), K. McLean (LANL) D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/NRC), J. Tueller (GSFC) on behalf of the Swift-BAT team: Using the full data set from the recent telemetry downlink, we report further analysis of Swift-BAT Trigger #147478 (Covino, et al., GCN 3665). The ground-analysis position is RA,Dec 246.177,-27.525 (J2000) with an uncertainty of 3 arcmin (radius, 90%, stat+sys). T90 is 3 +- 1 sec. The lightcurve has an initial hard FRED peak at T+0.00 sec (FWHM of 0.256 sec) and there is a smaller much softer peak at T+1.00 sec. Fitting a simple power law over the full interval from T-1.0 to T+3.0 seconds, the photon index is 1.71 +/- 0.16 with a fluence of 6.3 +/- 1.0 X 10^-7 erg/cm^2. The peak flux in a 1-sec wide window starting at T+0.04 seconds is 3.9 +/- 0.3 ph/cm^2/sec. All values are in the 15-350 keV band at the 90% confidence level. Given the second emission peak at T+1, the T90 of 3 sec, and the power law index value of 1.71, we can not confirm, nor rule out, that this burst falls into the short-burst category. However, in the energy range above 25 keV, the second, softer peak and subsequent emission is much less prominent, and so it is likely that BATSE would have classified this as a short GRB.