TITLE: GCN CIRCULAR NUMBER: 13806 SUBJECT: GRB 120922A: Swift-BAT refined analysis DATE: 12/09/23 13:36:02 GMT FROM: Scott Barthelmy at NASA/GSFC H. A. Krimm (GSFC/USRA), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), 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), V. N. Yershov (UCL-MSSL) (i.e. the Swift-BAT team): Using the data set from T-239 to T+303 sec from recent telemetry downlinks, we report further analysis of BAT GRB 120922A (trigger #534394) (Yershov, et al., GCN Circ. 13793). The BAT ground-calculated position is RA, Dec = 234.758, -20.181 deg, which is RA(J2000) = 15h 39m 02.0s Dec(J2000) = -20d 10' 51.8" with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment). The partial coding was 33%. The mask-weighted light curve shows low-level emission starting at T-200 sec, possibly sooner before the data capture started, with peaks at ~T_0, ~T+60, & ~T+105 sec, and ending at ~T+205 sec. T90 (15-350 keV) is 173 +- 33 sec (estimated error including systematics). The time-averaged spectrum from T-22.58 to T+215.73 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 1.58 +- 0.36, and Epeak of 38.2 +- 0.0 keV (chi squared 54.3 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 6.2 +- 0.7 x 10^-6 erg/cm2 and the 1-sec peak flux measured from T+99.21 sec in the 15-150 keV band is 2.0 +- 0.2 ph/cm2/sec. A fit to a simple power law gives a photon index of 2.09 +- 0.08 (chi squared 61.1 for 57 d.o.f.). 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/534394/BA/