TITLE: GCN CIRCULAR NUMBER: 17637 SUBJECT: GRB 150323C, Swift-BAT refined analysis DATE: 15/03/24 20:28:56 GMT FROM: Amy Lien at GSFC D. M. Palmer (LANL), Amaral-Rogers (U Leicester), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), T. Sakamoto (AGU), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Using the data set from T-274 to T+800 sec from the recent telemetry downlink, we report further analysis of BAT GRB 150323C (trigger #636005) (Amaral-Rogers, et al., GCN Circ. 17621). The BAT ground-calculated position is RA, Dec = 192.625, 50.165 deg which is RA(J2000) = 12h 50m 30.1s Dec(J2000) = +50d 09' 55.3" with an uncertainty of 2.4 arcmin, (radius, sys+stat, 90% containment). The partial coding was 26%. The mask-weighted light curve shows several weak overlapping pulses. The main burst structure starts at ~ T-20 s and ends at ~T+20 s, followed by another weaker pulse lasting till ~ T+160 s. T90 (15-350 keV) is 159.4 +- 54.0 sec (estimated error including systematics). The time-averaged spectrum from T-22.9 to T+166.3 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.09 +- 0.32. The fluence in the 15-150 keV band is 1.3 +- 0.3 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+5.98 sec in the 15-150 keV band is 1.1 +- 0.3 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/636005/BA/