TITLE: GCN CIRCULAR NUMBER: 27771 SUBJECT: GRB 200519A: Swift-BAT refined analysis DATE: 20/05/21 03:38:57 GMT FROM: Amy Lien at GSFC M. Stamatikos (OSU), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), B. Sbarufatti (PSU), T. N. Ukwatta (LANL) (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 200519A (trigger #973140) (Sbarufatti et al., GCN Circ. 27756). The BAT ground-calculated position is RA, Dec = 255.319, -30.393 deg which is RA(J2000) = 17h 01m 16.6s Dec(J2000) = -30d 23' 35.6" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 99%. The mask-weighted light curve shows a multi-peaked structure that starts at ~T0 and ends at ~T+100 s. The three main peaks occur at ~T+1 s, ~T+24 s, and ~T+75 s, respectively. T90 (15-350 keV) is 71.88 +- 1.28 sec (estimated error including systematics). The time-averaged spectrum from T-0.45 to T+103.00 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.42 +- 0.03. The fluence in the 15-150 keV band is 1.2 +- 0.02 x 10^-05 erg/cm2. The 1-sec peak photon flux measured from T+23.53 sec in the 15-150 keV band is 20.6 +- 0.5 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/973140/BA/