TITLE: GCN CIRCULAR NUMBER: 17795 SUBJECT: GRB 150430A: Swift-BAT refined analysis DATE: 15/04/30 15:04:52 GMT FROM: Scott Barthelmy at NASA/GSFC H. A. Krimm (GSFC/USRA), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), V. D'Elia (ASDC), N. Gehrels (GSFC), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Using the data set from T-240 to T+962 sec from recent telemetry downlinks, we report further analysis of BAT GRB 150430A (trigger #639433) (D'Elia, et al., GCN Circ. 17789). The BAT ground-calculated position is RA, Dec = 326.481, -27.919 deg, which is RA(J2000) = 21h 45m 55.5s Dec(J2000) = -27d 55' 07.9" with an uncertainty of 1.6 arcmin, (radius, sys+stat, 90% containment). The partial coding was 5%. The mask-weighted light curve shows several peaks starting at ~T-10 sec, the hightest peak at ~T+2 sec, the last peak at ~T+97 sec, and ending at ~T+110 sec. T90 (15-350 keV) is 107.1 +- 6.7 sec (estimated error including systematics). The time-averaged spectrum from T-11.64 to T+108.70 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.43 +- 0.12. The fluence in the 15-150 keV band is 6.9 +- 0.5 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+0.97 sec in the 15-150 keV band is 5.0 +- 1.0 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/639433/BA/