TITLE: GCN CIRCULAR NUMBER: 11945 SUBJECT: GRB 110420A: Swift-BAT refined analysis DATE: 11/04/20 23:59:45 GMT FROM: Scott Barthelmy at NASA/GSFC GRB 110420A: Swift-BAT refined analysis H. A. Krimm (GSFC/USRA), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), V. Mangano (INAF-IASFPA), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (GWU) (i.e. the Swift-BAT team): Using the data set from T-61 to T+242 sec from recent telemetry downlinks, we report further analysis of BAT GRB 110420A (trigger #451757) (Mangano, et al., GCN Circ. 11941). The BAT ground-calculated position is RA, Dec = 2.164, -37.877 deg which is RA(J2000) = 00h 08m 39.3s Dec(J2000) = -37d 52' 35.5" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 15%. The mask-weighted light curve shows a single peak with some structure starting at ~T-15 sec, peaking at ~T+8 sec, and ending at ~T+35 sec. T90 (15-350 keV) is 11.8 +- 0.9 sec (estimated error including systematics). The time-averaged spectrum from T-0.1 to T+16.0 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.30 +- 0.07. The fluence in the 15-150 keV band is 5.9 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+8.04 sec in the 15-150 keV band is 14.0 +- 0.9 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/451757/BA/