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Planck 2015 results. XI. CMB power spectra, likelihoods, and robustness of parameters

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posted on 2023-06-09, 04:42 authored by Antony LewisAntony Lewis, Dipak MunshiDipak Munshi, The Planck Collaboration
This paper presents the Planck 2015 likelihoods, statistical descriptions of the 2-point correlations of CMB data, using the hybrid approach employed previously: pixel-based at l<30 and a Gaussian approximation to the distribution of spectra at higher l . The main improvements are the use of more and better processed data and of Planck polarization data, and more detailed foreground and instrumental models, allowing further checks and enhanced immunity to systematics. Progress in foreground modelling enables a larger sky fraction. Improvements in processing and instrumental models further reduce uncertainties. For temperature, we perform an analysis of end-to-end instrumental simulations fed into the data processing pipeline; this does not reveal biases from residual instrumental systematics. The ? CDM cosmological model continues to offer a very good fit to Planck data. The slope of primordial scalar fluctuations, n s , is confirmed smaller than unity at more than 5{\sigma} from Planck alone. We further validate robustness against specific extensions to the baseline cosmology. E.g., the effective number of neutrino species remains compatible with the canonical value of 3.046. This first detailed analysis of Planck polarization concentrates on E modes. At low l we use temperature at all frequencies and a subset of polarization. The frequency range improves CMB-foreground separation. Within the baseline model this requires a reionization optical depth t=0.078±0.019 , significantly lower than without high-frequency data for explicit dust monitoring. At high l we detect residual errors in E, typically O(µ K 2 ); we recommend temperature alone as the high-l baseline. Nevertheless, Planck high-l polarization allows a separate determination of ? CDM parameters consistent with those from temperature alone.

Funding

Precision cosmological parameters : CosmoPars; G1365; EUROPEAN UNION; 616170 ERC-2013-CoG

Astrophysics and Cosmology - Sussex Consolidated Grant; G1291; STFC-SCIENCE AND TECHNOLOGY FACILITIES COUNCIL; ST/L000652/1

History

Publication status

  • Published

File Version

  • Published version

Journal

Astronomy and Astrophysics

ISSN

0004-6361

Publisher

EDP Sciences

Issue

a11

Volume

594

Department affiliated with

  • Physics and Astronomy Publications

Research groups affiliated with

  • Astronomy Centre Publications

Full text available

  • Yes

Peer reviewed?

  • Yes

Legacy Posted Date

2017-01-12

First Open Access (FOA) Date

2017-01-12

First Compliant Deposit (FCD) Date

2017-01-12

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