TITLE: GCN CIRCULAR NUMBER: 23914 SUBJECT: GRB 190220A: Swift-BAT refined analysis DATE: 19/02/20 17:59:59 GMT FROM: Amy Lien at GSFC S. D. Barthelmy (GSFC), J. R. Cummings (CPI), H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), K. L. Page (U Leicester), 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 190220A (trigger #889785) (Page et al., GCN Circ. 23908). The BAT ground-calculated position is RA, Dec = 330.128, -76.669 deg which is RA(J2000) = 22h 00m 30.7s Dec(J2000) = -76d 40' 10.1" with an uncertainty of 1.3 arcmin, (radius, sys+stat, 90% containment). The partial coding was 46%. The mask-weighted light curve shows a single-pulse structure that starts at ~T0, peaks at ~T+2 s, and ends at ~T+12 s. T90 (15-350 keV) is 10.0 +- 2.0 sec (estimated error including systematics). The time-averaged spectrum from T-0.12 to T+11.88 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 0.79 +- 0.77, and Epeak of 40.3 +- 6.7 keV (chi squared 60.03 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 8.9 +- 1.0 x 10^-7 erg/cm2 and the 1-sec peak flux measured from T+1.88 sec in the 15-150 keV band is 2.6 +- 0.4 ph/cm2/sec. A fit to a simple power law gives a photon index of 2.03 +- 0.13 (chi squared 70.39 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/889785/BA/