TITLE: GCN CIRCULAR NUMBER: 20076 SUBJECT: GRB 161017A: Swift-BAT refined analysis DATE: 16/10/18 17:08:51 GMT FROM: Tilan Ukwatta at LANL J. R. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC), 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), E. Troja (NASA/GSFC/UMCP), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Using the data set from T-239 to T+833 sec from the recent telemetry downlink, we report further analysis of BAT GRB 161017A (trigger #718023) (Troja, et al., GCN Circ. 20064). The BAT ground-calculated position is RA, Dec = 142.770, 43.125 deg which is RA(J2000) = 09h 31m 04.8s Dec(J2000) = +43d 07' 29.0" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 100%. The mask-weighted light curve shows two main episodes. The first multi-peak episode starts around T-5 sec, and ends at ~T+50 sec. The second relatively weaker episode starts at ~T+60 sec and ends around T+250 sec. T90 (15-350 keV) is 216.3 +- 6.9 sec (estimated error including systematics). The time-averaged spectrum from T-4.88 to T+233.42 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.55 +- 0.06. The fluence in the 15-150 keV band is 5.3 +- 0.2 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from T+17.78 sec in the 15-150 keV band is 2.8 +- 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/718023/BA/