TITLE: GCN CIRCULAR NUMBER: 11818 SUBJECT: GRB 110319B BAT refined analysis DATE: 11/03/22 15:38:58 GMT FROM: Jay R. Cummings at NASA/GSFC/Swift D. M. Palmer (LANL), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), A. Melandri (INAF-OAB), T. Sakamoto (GSFC/UMBC), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team): Using the data set from T-48 to T+52 sec, we report further analysis of GRB 110319B (Cummings, et al., GCN Circ. 11813). The refined BAT position is RA, Dec = 326.088, -56.774 deg, which is RA(J2000) = 21h 44m 21.1s Dec(J2000) = -56d 46m 26s with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). This position is 33 arcsec from the XRT position of the candidate afterglow. The partial coding was 100%. The mask-weighted light curve shows a single FRED peak starting at ~T-3 sec, peaking at ~T0, and ending at ~T+20 sec. T90 (15-350 keV) is 14.5 +- 2 sec (estimated error including systematics). The time-averaged spectrum from T-3.5 to T+16.5 sec is best fit by a simple power law. This fit gives a photon index 1.39 +- 0.05. For this model the total fluence in the 15-150 keV band is 1.0 +- 0.1 x 10-6 erg/cm2 and the 1-sec peak flux measured from T0 sec in the 15-150 keV band is 1.25 +- 0.15 ph/cm2/sec.