Planck data reconsidered

David N. Spergel, Raphael Flauger, Renée HloŽek

Research output: Contribution to journalArticlepeer-review

87 Scopus citations


The tension between the best fit parameters derived by the Planck team and a number of other astronomical measurements suggests either systematics in the astronomical measurements, systematics in the Planck data, the need for new physics, or a combination thereof. We reanalyze the Planck data and find that the 217GHz×217GHz detector set spectrum used in the Planck analysis is responsible for some of this tension. We use a map-based foreground cleaning procedure, relying on a combination of 353 GHz and 545 GHz maps to reduce residual foregrounds in the intermediate frequency maps used for cosmological inference. For our baseline data analysis, which uses 47% of the sky and makes use of both 353 and 545 GHz data for foreground cleaning, we find the ΛCDM cosmological parameters Ωch2=0.1170±0.0025, ns=0.9686±0.0069, H0=68.0±1.1kms-1Mpc-1, Ωbh2=0.02197±0.00026, ln1010As=3.082±0.025, and τ=0.090±0.013. While in broad agreement with the results reported by the Planck team, these revised parameters imply a universe with a lower matter density of Ωm=0.302±0.015, and parameter values generally more consistent with pre-Planck CMB analyses and astronomical observations. We compare our cleaning procedure with the foreground modeling used by the Planck team and find good agreement. The difference in parameters between our analysis and that of the Planck team is mostly due to our use of cross-spectra from the publicly available survey maps instead of their use of the detector set cross-spectra which include pixels only observed in one of the surveys. We show evidence suggesting residual systematics in the detector set spectra used in the Planck likelihood code, which is substantially reduced for our spectra. Using our cleaned survey cross-spectra, we recompute the limit on neutrino species and find Neff=3.34±0.35. We also recompute limits on the ns-r plane, and neutrino mass constraints.

Original languageEnglish (US)
Article number023518
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Issue number2
StatePublished - Jan 27 2015

All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics
  • Physics and Astronomy (miscellaneous)


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