TITLE: GCN CIRCULAR NUMBER: 17445 SUBJECT: GRB 150211A: Swift-BAT refined analysis DATE: 15/02/11 20:35:19 GMT FROM: Scott Barthelmy at NASA/GSFC W. H. Baumgartner (GSFC/UMBC), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), R. L. C. Starling (U Leicester), J. Tueller (GSFC), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Using the data set from T-61 to T+242 sec from recent telemetry downlinks, we report further analysis of BAT GRB 150211A (trigger #630714) (Starling, et al., GCN Circ. 17434). The BAT ground-calculated position is RA, Dec = 254.846, 55.390 deg, which is RA(J2000) = 16h 59m 23.0s Dec(J2000) = +55d 23' 23.2" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 16%. The mask-weighted light curve shows several overlapping peaks starting at ~T-10 sec, peaking at ~T+5 sec, and ending at ~T+30 sec. T90 (15-350 keV) is 13.6 +- 2.0 sec (estimated error including systematics). The time-averaged spectrum from T-11.24 to T+9.18 sec is best fit by a Double Blackbody. This fit gives a kT1 = 7.99 +2.8/-2.1 keV, kT2 = 24.7 +7.5/-3.2 keV, and (R1/D10)^2 = 6.0 +9.1/-3.3 and R2/D10)^2 = 0.22 +0.11/-0.15. (chi squared 74.8 for 59 d.o.f.). For this model the total fluence in the 15-150 keV band is 9.9 +- 1.2 x 10^-7 erg/cm2 and the 1-sec peak flux measured from T+4.36 sec in the 15-150 keV band is 12 +- 1 ph/cm2/sec. A Cutoff PL has an Epeak of 123.4 +- 27.5 keV (chi squared 81.8 for 56 d.o.f.). And for completeness, the fit to a simple power law gives a photon index of 1.28 +- 0.05 (chi squared 107 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/630714/BA/