Cosmological Parameters Degeneracies and Non-Gaussian Halo Bias

Abstract

We study the impact of the cosmological parameters uncertainties on the measurements of primordial non-Gaussianity through the large-scale non-Gaussian halo bias effect. While this is not expected to be an issue for the standard LCDM model, it may not be the case for more general models that modify the large-scale shape of the power spectrum. We consider the so-called local non-Gaussianity model and forecasts from planned surveys, alone and combined with a Planck CMB prior. In particular, we consider EUCLID- and LSST-like surveys and forecast the correlations among $f_{\mathrm{NL}}$ and the running of the spectral index ${\alpha }_s$, the dark energy equation of state $w$, the effective sound speed of dark energy perturbations $c_s^2$, the total mass of massive neutrinos $M_{\nu }=\sum m_{\nu }$, and the number of extra relativistic degrees of freedom $N_{\nu }^{rel}$. Neglecting CMB information on $f_{\mathrm{NL}}$ and scales $k>0.03h$/Mpc, we find that, if $N_{\nu }^{\mathrm{rel}}$ is assumed to be known, the uncertainty on cosmological parameters increases the error on $f_{\mathrm{NL}}$ by 10 to 30% depending on the survey. Thus the $f_{\mathrm{NL}}$ constraint is remarkable robust to cosmological model uncertainties. On the other hand, if $N_{\nu }^{\mathrm{rel}}$ is simultaneously constrained from the data, the $f_{\mathrm{NL}}$ error increases by $\sim 80$. Finally, future surveys which provide a large sample of galaxies or galaxy clusters over a volume comparable to the Hubble volume can measure primordial non-Gaussianity of the local form with a marginalized 1--$\sigma$ error of the order $\Delta f_{\mathrm{NL}}\sim 2-5$, after combination with CMB priors for the remaining cosmological parameters. These results are competitive with CMB bispectrum constraints achievable with an ideal CMB experiment.

17 pages, 1 figure added, typos corrected, comments added, matches the published version

References in corpus (18)

• Seven-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• Three Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Polarization Analysis
• Primordial Non-Gaussianities from Inflation Models
• Cosmological Constraints from the Clustering of the Sloan Digital Sky Survey DR7 Luminous Red Galaxies
• Effects of Scale-Dependent Non-Gaussianity on Cosmological Structures
• Detection of primordial non-Gaussianity (fNL) in the WMAP 3-year data at above 99.5% confidence
• The bispectrum of galaxies from high-redshift galaxy surveys: primordial non-Gaussianity and non-linear galaxy bias
• Primordial non-gaussianity, statistics of collapsed objects, and the Integrated Sachs-Wolfe effect
• Robust Neutrino Constraints by Combining Low Redshift Observations with the CMB
• Fast Estimator of Primordial Non-Gaussianity from Temperature and Polarization Anisotropies in the Cosmic Microwave Background
• 21-cm Background Anisotropies Can Discern Primordial Non-Gaussianity
• The bispectrum of redshifted 21-cm fluctuations from the dark ages
• Finding Evidence for Massive Neutrinos using 3D Weak Lensing
• Empirical H-alpha emitter count predictions for dark energy surveys
• Can a galaxy redshift survey measure dark energy clustering?
• Optimal dataset combining in f_nl constraints from large scale structure in an idealised case
• Impact of Uncertainties in the Cosmological Parameters on the Measurement of Primordial non-Gaussianity

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