Joint Analysis of BICEP2/Keck Array and Planck Data

By BICEP2Keck, P. Ade, N. Aghanim, Z. Ahmed, R. Aikin, K. Alexander, M. Arnaud, J. Aumont, C. Baccigalupi, A. Banday and 267 more. 2015

918 citations recorded by the source corpus.

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 r0.05<0.12 at 95% confidence. Marginalizing over dust and r, lensing B modes are detected at 7.0σ significance.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/62f54d0fd1293b2e9917e55414f64d60d32ce26d

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In Astronomy and Astrophysics

1. Andrei Linde
2. R. Kallosh
3. J. J. Carrasco
4. D. Roest
5. E. Kovetz
6. A. Sesana
7. M. Kamionkowski
8. C. Caprini

Citations in the corpus

• On the possibility of large axion moduli spaces (2014, background): “Although recent measurements of B-mode polarization by the BICEP2 collaboration [6] can be explained largely by dust [7, 8], a primordial tensorto-scalar ratio r & 0.”
• Multimodal Data Fusion: An Overview of Methods, Challenges, and Prospects (2015, background): “Power spectra are useful to compare outcomes of different experiments that measure the CMB, e.g., Planck and BICEP2/Keck [168], whereas cosmological parameters form the link, via the ΛCDM model, with datasets that do not involve astrophysical observations, e.g., high-energy physics at CERN [56].”
• Planck 2015 results: XIX. Constraints on primordial magnetic fields (2015, neutral): “In the literature there are several previous studies that already derived constraints on PMFs using different combinations of observed CMB power spectra (Caprini 2010; Yamazaki et al. 2010; Paoletti & Finelli 2011; Shaw & Lewis 2012; Paoletti & Finelli 2013; Ade et al. 2015).”
• The Polarbear-2 and the Simons Array Experiments (2015, background): “Planck’s report on the CMB foregrounds suggests that polarized foregrounds such as synchrotron radiation and dust emission need to be carefully subtracted for accurate CMB polarization measurements [11,12].”
• Science with the space-based interferometer eLISA. III: probing the expansion of the universe using gravitational wave standard sirens (2016, background): “nteresting bounds on the stochastic GW background produced by massive black-hole binaries (MBHBs) [9,10]. The B-mode polarisation of the CMB gives access to the very low frequency band 10 18 10 16 Hz [11], targeting the GW background sourced during in ation, or similar scenarios where GWs are genera”