TITLE: GCN CIRCULAR NUMBER: 17044 SUBJECT: GRB 141109A: Swift-BAT refined analysis DATE: 14/11/09 18:02:52 GMT FROM: Scott Barthelmy at NASA/GSFC W. H. Baumgartner (GSFC/UMBC), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), P. D'Avanzo (INAF-OAB), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), 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-239 to T+963 sec from recent telemetry downlinks, we report further analysis of BAT GRB 141109A (trigger #618024) (D'Avanzo, et al., GCN Circ. 17037). The BAT ground-calculated position is RA, Dec = 144.563, -0.581 deg, which is RA(J2000) = 09h 38m 15.0s Dec(J2000) = -00d 34' 52.4" with an uncertainty of 3.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 60%. The mask-weighted light curve shows a weak peak from ~T+0 to ~T+40 sec, then the bulk of the emission came from ~T+60 to ~T+190 sec, and then a tail extending out to ~T+380 sec. T90 (15-350 keV) is 200 +- 47 sec (estimated error including systematics). The time-averaged spectrum from T+0.60 to T+323.15 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.52 +- 0.07. The fluence in the 15-150 keV band is 6.8 +- 0.3 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+117.39 sec in the 15-150 keV band is 2.5 +- 0.2 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/618024/BA/