TITLE: GCN CIRCULAR NUMBER: 17083 SUBJECT: GRB 141121A: Swift-BAT refined analysis DATE: 14/11/21 14:40:09 GMT FROM: Hans Krimm at NASA-GSFC H. A. Krimm (GSFC/USRA), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), 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 the recent telemetry downlink, we report further analysis of BAT GRB 141121A (trigger #619182) (Lien, et al., GCN Circ. 17075). The BAT ground-calculated position is RA, Dec = 122.665, 22.206 deg which is RA(J2000) = 08h 10m 39.5s Dec(J2000) = +22d 12' 22.5" with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment). The partial coding was 32%. The mask-weighted light curve shows a very broad multi-peaked structure with the first emission episode running from T-50 to T+450 sec, with at least four superimposed peaks. Then there is a return to baseline followed by another episode from T+550 to T+675 sec. The spacecraft slewed away from the burst position at around T+825 sec. T90 (15-350 keV) is 549.9 +- 37.4 sec (estimated error including systematics). The time-averaged spectrum from T+46.54 to T+663.07 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.73 +- 0.13. The fluence in the 15-150 keV band is 5.3 +- 0.4 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+230.14 sec in the 15-150 keV band is 0.9 +- 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/619182/BA/