TITLE: GCN CIRCULAR NUMBER: 15383 SUBJECT: GRB 131024B, Swift-BAT refined analysis DATE: 13/10/25 19:01:28 GMT FROM: Hans Krimm at NASA-GSFC W. H. Baumgartner (GSFC/UMBC), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (NASA/GSFC/ORAU), 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-61 to T+242 sec from the recent telemetry downlink, we report further analysis of BAT GRB 131024B (trigger #575754) (Krimm, et al., GCN Circ. 15371). The BAT ground-calculated position is RA, Dec = 144.464, 44.284 deg which is RA(J2000) = 09h 37m 51.3s Dec(J2000) = +44d 17' 02.1" with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment). The partial coding was 40%. The mask-weighted light curve shows activity starting around T-10 sec and continuing to ~T+100 sec. There are several weak peak superimposed. T90 (15-350 keV) is 64.00 +- 22 sec (estimated error including systematics). The time-averaged spectrum from T-12.59 to T+51.41 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 0.85 +- 0.23. The fluence in the 15-150 keV band is 1.2 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+10.91 sec in the 15-150 keV band is 0.1 +- 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/575754/BA/