TITLE: GCN CIRCULAR NUMBER: 14624 SUBJECT: GRB 130511A, Swift-BAT refined analysis DATE: 13/05/11 21:27:10 GMT FROM: Hans Krimm at NASA-GSFC M. Stamatikos (OSU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (NASA/GSFC/ORAU), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU),T. N. Ukwatta (MSU) (i.e. the Swift-BAT team): Using the data set from T-240 to T+950 sec from the recent telemetry downlink, we report further analysis of BAT GRB 130511A (trigger #555600) (Krimm, et al., GCN Circ. 14620). The BAT ground-calculated position is RA, Dec = 196.654, 18.709 deg which is RA(J2000) = 13h 06m 36.9s Dec(J2000) = +18d 42' 33.7" with an uncertainty of 2.3 arcmin, (radius, sys+stat, 90% containment). The partial coding was 57%. The mask-weighted light curve shows an initial sharp double-peak at T0 of duration ~0.5 seconds, transitioning to a FRED-like decay lasting ~5 seconds, after which the light curve returns to baseline. T90 (15-350 keV) is 5.43 +- 2.22 sec (estimated error including systematics). The time-averaged spectrum from T-0.07 to T+6.03 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.35 +- 0.31. The fluence in the 15-150 keV band is 2.2 +- 0.4 x 10^-07 erg/cm2. The 1-sec peak photon flux measured from T-0.09 sec in the 15-150 keV band is 1.3 +- 0.2 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/555600/BA/