Ade, P. A. R.14; Aghanim, N.4; Ahmed, Z.5; Aikin, R. W.15; Alexander, K. D.7; Arnaud, M.8; Aumont, J.4; Baccigalupi, C.9; Banday, A. J.10; Barkats, D.11; Barreiro, R. B.16; Linden-Vørnle, Michael1; Nørgaard-Nielsen, Hans Ulrik1; Christensen, P. R.13; Frejsel, A.13; Naselsky, P.13; Novikov, I.13
1 National Space Institute, Technical University of Denmark2 Astrophysics, National Space Institute, Technical University of Denmark3 Cardiff University4 Université de Paris-Sud5 Stanford University6 California Institute of Technology7 Harvard-Smithsonian Center for Astrophysics8 University Paris Diderot - Paris 79 International School for Advanced Studies10 Max Planck Institute11 Joint ALMA Observatory12 Universidad de Cantabria13 University of Copenhagen14 Cardiff University15 California Institute of Technology16 Universidad de Cantabria
We report the results of a joint analysis of data from BICEP2/Keck Array and Planck. BICEP2 and Keck Array have observed the same approximately 400 deg2 patch of sky centered on RA 0 h, Dec. -57.5°. The combined maps reach a depth of 57 nK deg in Stokes Q and U in a band centered at 150 GHz. Planck has observed the full sky in polarization at seven frequencies from 30 to 353 GHz, but much less deeply in any given region (1.2 μK deg in Q and U at 143 GHz). We detect 150×353 cross-correlation in B modes at high significance. We fit the single- and cross-frequency power spectra at frequencies ≥150 GHz to a lensed-ΛCDM model that includes dust and a possible contribution from inflationary gravitational waves (as parametrized by the tensor-to-scalar ratio r), using a prior on the frequency spectral behavior of polarized dust emission from previous Planck analysis of other regions of the sky. We find strong evidence for dust and no statistically significant evidence for tensor modes. We probe various model variations and extensions, including adding a synchrotron component in combination with lower frequency data, and find that these make little difference to the r constraint. Finally, we present an alternative analysis which is similar to a map-based cleaning of the dust contribution, and show that this gives similar constraints. The final result is expressed as a likelihood curve for r, and yields an upper limit r 0.05 < 0.12 at 95% confidence. Marginalizing over dust and r, lensing B modes are detected at 7.0σ significance.