TITLE: GCN CIRCULAR NUMBER: 18634 SUBJECT: Swift-BAT refined analysis of trigger 664624 from SGR J1819-1600 DATE: 15/11/22 21:22:32 GMT FROM: Scott Barthelmy at NASA/GSFC D. M. Palmer (LANL), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), 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-120 to T+242 sec from the recent telemetry downlinks, we report further analysis of an outburst from SGR J1819-1600 (trigger #664624) (Page, et al., GCN Circ. 18632). The BAT ground-calculated position is RA, Dec = 274.714, -15.981 deg, which is RA(J2000) = 18h 18m 51.4s Dec(J2000) = -15d 58' 52.6" with an uncertainty of 2.5 arcmin, (radius, sys+stat, 90% containment). The partial coding was 86%. The mask-weighted light curve shows a single spike starting at T_zero. T90 (15-350 keV) is 0.032 +- 0.14 sec (estimated error including systematics). The time-averaged spectrum from T+0.000 to T+0.032 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 0.93 +- 0.38. The fluence in the 15-150 keV band is 1.5 +- 0.4 x 10^-8 erg/cm2. The 1-sec peak photon flux measured from T-0.00 sec in the 15-150 keV band is 4.8 +- 1.2 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/664624/BA/