TITLE: GCN CIRCULAR NUMBER: 17406 SUBJECT: GRB 150204A BAT refined analysis DATE: 15/02/04 19:53:28 GMT FROM: Jay R. Cummings at NASA/GSFC/Swift M. Stamatikos (OSU), C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (CPI.com), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), D. M. Palmer (LANL), T. Sakamoto (AGU), J. Tueller (GSFC), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): We report further analysis of GRB 150204A. The best BAT position is the same as reported earlier (Cummings, GCN # 17404), RA, Dec 160.241, -64.043, which is: RA (J2000) 10h 40m 57.8s Dec (J2000) -64d 02' 34" with an estimated 90% uncertainty radius of 1.5 arcmin. The source was 77% coded at the time of the burst. The burst was a single symmetric cusp. T90 was 12 +- 2 seconds. A simple powerlaw function is the best fit to the BAT spectrum. The photon index is 1.62 +- 0.10. The fluence from 15 to 150 keV in 13 seconds was (8.0 +- 0.4) x 10^-7 ergs/cm^2. The 1-second peak flux in this energy range was 1.85 +- 0.12 photons/cm^2. All uncertainties are 90% confidence. A Swift TOO has been approved.