Impact of uncertainties in the cosmological parameters on the measurement of primordial non-Gaussianity

2008/08/24 by M. Liguori, A. Riotto, Antonio Riotto · 5 citations
Physics and Astronomy · #Black Holes and Theoretical Physics #Cosmology and Gravitation Theories #Noncommutative and Quantum Gravity Theories #astro-ph #gr-qc #hep-ph

paper · pdf · doi:10.1103/physrevd.78.123004

published as Phys.Rev.D78:123004,2008 · 10 pages, 3 figures, submitted to Phys. Rev. D

arxiv created 2008/08/24 · openalex publication_date 2008/12/08 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

We study the impact of cosmological parameters' uncertainties on estimates of the primordial non-Gaussianity (NG) parameter f_NL in local and equilateral models of non-Gaussianity. We show that propagating these errors increases the f_NL 1\ensuremathσ uncertainty by a term \ensuremathδf_NL^local/f_NL^local\ensuremath≃16% for WMAP and \ensuremathδf_NL^local/f_NL^local\ensuremath≃5% for Planck in the local case, whereas for equilateral configurations the correction terms are \ensuremathδf_NL^equil/f_NL^equil\ensuremath≃14% and \ensuremathδf_NL^equil/f_NL^equil\ensuremath≃4%, respectively. If we assume for f_NL^local a central value ⟨f_NL^local⟩\ensuremath≃60, according to recent WMAP 5-year estimates, we obtain for Planck a final correction \ensuremathΔf_NL^local\ensuremath≃3. Although not dramatic, this correction is at the level of the expected estimator uncertainty for Planck, and should then be taken into account when quoting the significance of an eventual future detection. In current estimates of f_NL the cosmological parameters are held fixed at their best-fit values. We finally note that the impact of uncertainties in the cosmological parameters on the final f_NL error bar would become totally negligible if the parameters were allowed to vary in the analysis and then be marginalized over.

Citations

• The shape of non-Gaussianities
• Non-Gaussian features of primordial fluctuations in single field inflationary models
• Non-Gaussianity from Inflation: Theory and Observations

Cited by

• On the non-Gaussianity from recombination
• The effects of primordial non-Gaussianity on the cosmological reionization
• Constraints on primordial non-Gaussianity from galaxy-CMB lensing cross correlation
• Baryon history and cosmic star formation in non-Gaussian cosmological models: numerical simulations
• Constraining scale-dependent non-Gaussianity with future large-scale structure and the CMB

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• New constraints on primordial non-Gaussianity from missing two-loop contributions of scalar induced gravitational waves
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