TITLE: GCN CIRCULAR NUMBER: 13310 SUBJECT: GRB 120521A: Swift-BAT refined analysis DATE: 12/05/21 11:37:22 GMT FROM: Scott Barthelmy at NASA/GSFC J. R. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), M. M. Chester (PSU), 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+363 sec from recent telemetry downlinks, we report further analysis of BAT GRB 120521A (trigger #522578) (Chester, et al., GCN Circ. 13302). The BAT ground-calculated position is RA, Dec = 148.692, -49.422 deg, which is RA(J2000) = 09h 54m 46.1s Dec(J2000) = -49d 25' 17.8" with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment). The partial coding was 100%. The mask-weighted light curve shows FRED pulse starting at ~T+0.0, peaking at ~T+0.1, and ending at ~T+1.0 sec. T90 (15-350 keV) is 0.45 +- 0.08 sec (estimated error including systematics). The time-averaged spectrum from T+0.02 to T+0.56 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 0.98 +- 0.22. The fluence in the 15-150 keV band is 7.8 +- 1.1 x 10^-8 erg/cm2. The 1-sec peak photon flux measured from T-0.21 sec in the 15-150 keV band is 0.9 +- 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/522578/BA/