TITLE: GCN CIRCULAR NUMBER: 12831 SUBJECT: AXP 4U 0142+61: Swift-BAT refined analysis (trigger 511611) DATE: 12/01/13 00:33:18 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team): Using the data set from T-239 to T+420 sec from recent telemetry downlinks, we report further analysis of BAT trigger #511611 on AXP 4U 0142+61 (Barthelmy, et al., GCN Circ. 12829). The partial coding was 84%. The mask-weighted light curve shows a single FRED-like peak starting at T_0 and lasting for ~250 msec. T90 (15-350 keV) is 0.024 +- 0.009 sec (estimated error including systematics). The time-averaged spectrum from T+0.008 to T+0.036 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.32 +- 0.50. The fluence in the 15-150 keV band is 6.8 +- 2.1 x 10^-9 erg/cm2. The 1-sec peak photon flux measured from T-0.48 sec in the 15-150 keV band is 0.4 +- 0.1 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/511611/BA/