Joint Analysis of BICEP2/Keck Array and Planck Data
Abstract
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 deg^{2} 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 μ K deg in Q and U at 143 GHz). We detect 150 ×353 crosscorrelation in B modes at high significance. We fit the single and crossfrequency power spectra at frequencies ≥150 GHz to a lensedΛ CDM model that includes dust and a possible contribution from inflationary gravitational waves (as parametrized by the tensortoscalar 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 mapbased 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 7.0 σ significance.
 Publication:

Physical Review Letters
 Pub Date:
 March 2015
 DOI:
 10.1103/PhysRevLett.114.101301
 arXiv:
 arXiv:1502.00612
 Bibcode:
 2015PhRvL.114j1301B
 Keywords:

 98.70.Vc;
 04.80.Nn;
 95.85.Bh;
 98.80.Es;
 Background radiations;
 Gravitational wave detectors and experiments;
 Radio microwave;
 Observational cosmology;
 Astrophysics  Cosmology and Nongalactic Astrophysics;
 General Relativity and Quantum Cosmology;
 High Energy Physics  Phenomenology;
 High Energy Physics  Theory
 EPrint:
 Version updated to match published. Data and figures available for download at http://bicepkeck.org and http://pla.esac.esa.int/pla