TITLE: GCN CIRCULAR NUMBER: 19974 SUBJECT: GRB 161001A, Swift-BAT refined analysis (likely a short GRB) DATE: 16/10/01 16:29:32 GMT FROM: Amy Lien at GSFC 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), J. P. Norris (BSU), K. L. Page (U Leicester) 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-274 to T+962 sec from the recent telemetry downlink, we report further analysis of BAT GRB 161001A (trigger #714404) (Page, et al. GCN Circ. 19967). The BAT ground-calculated position is RA, Dec = 71.923, -57.261 deg which is RA(J2000) = 04h 47m 41.5s Dec(J2000) = -57d 15' 39.8" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 78%. The mask-weighted light curve shows several overlapping pulses that stars at ~T-0.3, and ends at ~T+3 s. The highest peak occurs at ~ T+1.6 s. T90 (15-350 keV) is 2.6 +- 0.4 sec (estimated error including systematics). The time-averaged spectrum from T-0.2 to T+3.1 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.14 +- 0.09. The fluence in the 15-150 keV band is 6.7 +- 0.4 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+1.40 sec in the 15-150 keV band is 3.5 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level. Using a 16-ms binned light curve, the lag analysis finds a lag of 7 (+/- 13) ms for the 100-350 keV to 25-50 keV band, and -7.5 (+26, -19) ms for the 50-100 keV to 15-25 keV band, which is consistent with those of a short GRB. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/714404/BA/