TITLE: GCN CIRCULAR NUMBER: 17239 SUBJECT: GRB 141225A: Swift-BAT refined analysis DATE: 14/12/26 14:29:58 GMT FROM: Hans Krimm at NASA-GSFC S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), 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), 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 141225A (trigger #622476) (D'Avanzo, et al., GCN Circ. 17229). The BAT ground-calculated position is RA, Dec = 138.754, 33.774 deg which is RA(J2000) = 09h 15m 01.1s Dec(J2000) = +33d 46' 27.7" with an uncertainty of 2.2 arcmin, (radius, sys+stat, 90% containment). The partial coding was 26%. The burst location first entered the BAT field of view at ~T-40 sec, during a pre-planned slew. The mask-weighted light curve shows a single FRED-shaped peak, beginning at T+5 sec, peaking at T+12 sec and returning to baseline level by T+50 sec. T90 (15-350 keV) is 40.24 +- 7.04 sec sec (estimated error including systematics). The time-averaged spectrum from T+5.50 to T+50.68 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.32 +- 0.15. The fluence in the 15-150 keV band is 2.5 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+11.76 sec in the 15-150 keV band is 1.3 +- 0.4 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/622476/BA/