TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5578 SUBJECT: GRB 060919, Swift-BAT refined analysis DATE: 06/09/19 14:55:29 GMT FROM: Scott Barthelmy at NASA/GSFC G. Sato (GSFC/ISAS), L. Barbier (GSFC), S. D. Barthelmy (GSFC), J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC), C. Guidorzi (Univ Bicocca&INAF-OAB), D. Hullinger (BYU-Idaho), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/ORAU), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC) on behalf of the Swift-BAT team: Using the data set from T-239 to T+950 sec from recent telemetry downlinks, we report further analysis of BAT GRB 060919 (trigger #230115) (Guidorzi, et al., GCN Circ. 5575). The BAT ground-calculated position is RA,Dec = 276.900, -50.994 deg {18h 27m 36.0s, -50d 59' 39.8"} (J2000) +- 1.6 arcmin, (radius, sys+stat, 90% containment). The partial coding was 29%. There is an initial FRED peak starting at T-1 sec, peaking at T+0, and lasting out to T+5 sec. There is smaller, 4-sec wide FRED-like peak starting at T+6 sec. There is an even smaller, 4-sec wide peak centered at T+24 sec. We note that our initial circular using the raw TDRSS rate lightcurves described a second episode of emission at T+300 sec. Now using the masked-tagged light curves, this second episode was due to a noisy detector in the instrument. T90 (15-350 keV) is 9.1 +- 0.2 sec (estimated error including systematics). The time-averaged spectrum from T-1.0 to T+9.0 is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.85 +- 0.19. The fluence in the 15-150 keV band is 5.5 +- 0.6 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T-0.49 sec in the 15-150 keV band is 2.2 +- 0.3 ph/cm2/sec. All the quoted errors are at the 90% confidence level.