TITLE: GCN CIRCULAR NUMBER: 8030 SUBJECT: GRB 080727B, Swift-BAT refined analysis DATE: 08/07/27 17:12:48 GMT FROM: Takanori Sakamoto at NASA/GSFC W. Baumgartner (GSFC/UMBC), S. D. Barthelmy (GSFC), J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), K. McLean (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. Ukwatta (GWU) (i.e. the Swift-BAT team): Using the data set from T-120 to T+182 sec from the recent telemetry downlink, we report further analysis of BAT GRB 080727B (trigger #318101) (Immler, et al., GCN Circ. 8022). The BAT ground-calculated position is RA, Dec = 276.871, 1.173 deg which is RA(J2000) = 18h 27m 29.1s Dec(J2000) = +01d 10' 23.2" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 69%. The mask-weighted light curve shows two big FRED-like pulses from T-0.5 to T+3 sec and from T+5.5 to T+9.5 sec. There are several pulses starting at T+2.5, T+7.2, T+7.5, and T+8.8 sec. T90 (15-350 keV) is 8.6 +- 0.2 sec (estimated error including systematics). The time-averaged spectrum from T-0.2 to T+9.4 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 0.80 +- 0.17, and Epeak of 226.6 +- 120.2 keV (chi squared 43.60 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 3.1 +- 0.1 x 10^-06 erg/cm2 and the 1-sec peak flux measured from T-0.04 sec in the 15-150 keV band is 7.6 +- 0.2 ph/cm2/sec. A fit to a simple power law gives a photon index of 1.12 +- 0.04 (chi squared 54.09 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/318101/BA/