2017/05/08 by The POLARBEAR Collaboration, P. A. R. Ade, M. Aguilar +79 · 1 voice
Physics and Astronomy · #astro-ph.CO
paper · pdf · doi:10.3847/1538-4357/aa8e9f
published as The Astrophysical Journal, 848:141, 2017 · 16 pages, 10 figures. Minor changes to match the published version. For data and figures, see http://bolo.berkeley.edu/polarbear/data/polarbear_BB_2017/
arxiv published 2017/05/08 · arxiv created 2017/10/27 · arxiv updated 2017/10/27
We report an improved measurement of the cosmic microwave background (CMB) B-mode polarization power spectrum with the POLARBEAR experiment at 150 GHz. By adding new data collected during the second season of observations (2013-2014) to re-analyzed data from the first season (2012-2013), we have reduced twofold the band-power uncertainties. The band powers are reported over angular multipoles 500 ≤ ℓ ≤ 2100, where the dominant B-mode signal is expected to be due to the gravitational lensing of E-modes. We reject the null hypothesis of no B-mode polarization at a confidence of 3.1σ including both statistical and systematic uncertainties. We test the consistency of the measured B-modes with the Λ Cold Dark Matter (ΛCDM) framework by fitting for a single lensing amplitude parameter AL relative to the Planck best-fit model prediction. We obtain AL = 0.60 +0.26 -0.24 (\rm stat) +0.00 -0.04(\rm inst) ± 0.14 (\rm foreground) ± 0.04 (\rm multi), where AL=1 is the fiducial ΛCDM value, and the details of the reported uncertainties are explained later in the manuscript.