TITLE: GCN CIRCULAR NUMBER: 13052 SUBJECT: GRB 120312A: Swift-BAT refined analysis DATE: 12/03/12 22:24:54 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-240 to T+736 sec from the recent telemetry downlink, we report further analysis of BAT GRB 120312A (trigger #517566) (Stamatikos, et al., GCN Circ. 13049). The BAT ground-calculated position is RA, Dec = 251.812, 23.881 deg, which is RA(J2000) = 16h 47m 14.8s Dec(J2000) = +23d 52' 50.3" with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment). The partial coding was 35%. The mask-weighted light curve shows a single slightly symmetric peak starting at ~T-10 sec, peaking at ~T+0.5 sec, and ending at ~T+35 sec. T90 (15-350 keV) is 14.2 +- 3.4 sec (estimated error including systematics). The time-averaged spectrum from T-1.42 to T+15.87 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.72 +- 0.23. The fluence in the 15-150 keV band is 5.7 +- 0.8 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+0.95 sec in the 15-150 keV band is 1.3 +- 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/517566/BA/