TITLE: GCN CIRCULAR NUMBER: 19376 SUBJECT: GRB 160501A: Swift-BAT refined analysis DATE: 16/05/02 13:46:06 GMT FROM: Takanori Sakamoto at AGU C. B. Markwardt (GSFC), 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), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Using the data set from T-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 160501A (trigger #684679) (Cummings, et al., GCN Circ. 19365). The BAT ground-calculated position is RA, Dec = 286.389, -17.249 deg which is RA(J2000) = 19h 05m 33.2s Dec(J2000) = -17d 14' 54.8" with an uncertainty of 1.8 arcmin, (radius, sys+stat, 90% containment). The partial coding was 81%. The mask-weighted light curve a broad peak starting from T-80 sec, peaking at T+50 sec and ending at T+90 sec. T90 (15-350 keV) is 118 +- 19 sec (estimated error including systematics). The time-averaged spectrum from T-54.3 to T+72.6 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 0.6 +- 1.3, and Epeak of 28 +- 9 keV (chi squared 54.26 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 9.5 +- 1.3 x 10^-7 erg/cm2 and the 1-sec peak flux measured from T-54.38 sec in the 15-150 keV band is 0.5 +- 0.2 ph/cm2/sec. A fit to a simple power law gives a photon index of 2.4 +- 0.2 (chi squared 63.09 for 57 d.o.f.). 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/684679/BA/