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

By N. Aghanim, M. Arnaud, M. Ashdown, J. Aumont, C. Baccigalupi, A. Banday, Rita Belén Barreiro, J. Bartlett, N. Bartolo, E. Battaner and 213 more. 2015

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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 $\ell<30$ and a Gaussian approximation to the distribution of spectra at higher $\ell$. 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 $\Lambda$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 $\ell$ 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 $\tau=0.078\pm0.019$, significantly lower than without high-frequency data for explicit dust monitoring. At high $\ell$ we detect residual errors in E, typically O($\mu$K$^2$); we recommend temperature alone as the high-$\ell$ baseline. Nevertheless, Planck high-$\ell$ polarization allows a separate determination of $\Lambda$CDM parameters consistent with those from temperature alone.

Subfields: Astronomy and Astrophysics, Atomic and Molecular Physics, and Optics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/59a922829487a3f29ff27d31c701b59e9f1f24c3

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Citations in the corpus

Nonlocal gravity. Conceptual aspects and cosmological predictions (2017, methodology): “We also include the temperature+polarization (T+P) lensing data, using only the conservative multipole range ` = 40− 400 [126, 127].”
Rock ‘n’ roll solutions to the Hubble tension (2019, methodology): “• Planck: We use the Planck 2015 CMB temperature and polarization likelihoods [40] for both low-` and high-`, including all nuisance parameters and using the same prior distributiona as in the Planck analysis [7] for those.”
Current unknowns in the three-neutrino framework (2018, methodology): “Such Planck data were eventually supplemented with lensing potential power spectrum reconstruction data, and with optical depth HFI constraints (τHFI) [258].”