TITLE: GCN CIRCULAR NUMBER: 13572 SUBJECT: GRB 120803B: Swift-BAT refined analysis DATE: 12/08/03 17:47:01 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), J. L. Racusin (NASA/GSFC), 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-60 to T+243 sec from recent telemetry downlinks, we report further analysis of BAT GRB 120803B (trigger #529606) (Racusin, et al., GCN Circ. 12566). The BAT ground-calculated position is RA, Dec = 314.223, 53.298 deg, which is RA(J2000) = 20h 56m 53.6s Dec(J2000) = +53d 17' 54.2" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 58%. The mask-weighted light curve shows a FRED-like pulse starting at ~T-5 sec, peaking at ~T+6 sec, and returning to baseline ~T+60 sec (or possibly T+90 sec). T90 (15-350 keV) is 37.5 +- 7.9 sec (estimated error including systematics). The time-averaged spectrum from T-2.67 to T+49.16 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 0.84 +- 0.36, and Epeak of 117.8 +- 77.4 keV (chi squared 53.7 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 2.5 +- 0.5 x 10^-6 erg/cm2 and the 1-sec peak flux measured from T+4.49 sec in the 15-150 keV band is 1.5 +- 0.2 ph/cm2/sec. A fit to a simple power law gives a photon index of 1.36 +- 0.08 (chi squared 60.5 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/529606/BA/