Local Primordial Non-Gaussianities and Super-Sample Variance

Abstract

Fluctuations with wavelengths larger than the volume of a galaxy survey affect the measurement of the galaxy power spectrum within the survey itself. In the presence of local Primordial Non- Gaussianities (PNG), in addition to the super-sample matter density and tidal fluctuations, the large-scale gravitational potential also induces a modulation of the observed power spectrum. In this work we investigate this modulation by computing for the first time the response of the redshift-space galaxy power spectrum to the presence of a long wavelength gravitational potential, fully accounting for the stochastic contributions. For biased tracers new response functions arise due to couplings between the small-scale fluctuations in the density, velocity and gravitational fields, the latter through scale dependent bias operators, and the large-scale gravitational potential. We study the impact of the super-sample modes on the measurement of the amplitude of the primordial bispectrum of the local-shape, $f_{\mathrm{NL}}^{\mathrm{loc}}$, accounting for modulations of both the signal and the covariance of the galaxy power spectrum by the long modes. Considering DESI-like survey specifications, we show that in most cases super-sample modes cause little or no degradation of the constraints, and could actually reduce the errorbars on $f_{\mathrm{NL}}^{\mathrm{loc}}$ by (10 - 30)\%, if external information on the bias parameters is available.

15 pages, 4 figures

References in corpus (19)

• The DESI Experiment Part I: Science,Targeting, and Survey Design
• The imprints of primordial non-gaussianities on large-scale structure: scale dependent bias and abundance of virialized objects
• Measuring primordial non-gaussianity without cosmic variance
• Gravity and Large-Scale Non-local Bias
• Primordial non-gaussianity, statistics of collapsed objects, and the Integrated Sachs-Wolfe effect
• Planck 2018 results. IX. Constraints on primordial non-Gaussianity
• Primordial non-Gaussianity, scale-dependent bias, and the bispectrum of galaxies
• Separate Universe Simulations
• Constraints on primordial non-Gaussianity from 800,000 photometric quasars
• Position-dependent power spectrum of the large-scale structure: a novel method to measure the squeezed-limit bispectrum
• Analytic model for the matter power spectrum, its covariance matrix, and baryonic effects
• Super-Sample Signal
• Galaxy redshift-space bispectrum: the Importance of Being Anisotropic
• Using Large Scale Structure to test Multifield Inflation
• Joint likelihood function of cluster counts and $n$-point correlation functions: Improving their power through including halo sample variance
• Measuring the Tidal Response of Structure Formation: Anisotropic Separate Universe Simulations using TreePM
• Principal Shapes and Squeezed Limits in the Effective Field Theory of Large Scale Structure
• Anisotropic separate universe simulations
• On the equivalence between the effective cosmology and excursion set treatments of environment

Cited by in corpus (15)

• The observed galaxy power spectrum in General Relativity
• On the impact of galaxy bias uncertainties on primordial non-Gaussianity constraints
• Predictions for local PNG bias in the galaxy power spectrum and bispectrum and the consequences for $f_{\mathrm{NL}}$ constraints
• Local primordial non-Gaussianity from the large-scale clustering of photometric DESI luminous red galaxies
• Light Fields during Inflation from BOSS and Future Galaxy Surveys
• Large Scale Limit of the Observed Galaxy Power Spectrum
• Density reconstruction from biased tracers and its application to primordial non-Gaussianity
• Lagrangian approach to super-sample effects on biased tracers at field level: galaxy density fields and intrinsic alignments
• Super-sample covariance of the power spectrum, bispectrum, halos, voids, and their cross covariances
• Wide-angle effects in the galaxy bispectrum
• Neural network reconstruction of density and velocity fields from the 2MASS Redshift Survey
• Statistics of a single sky: constrained random fields and the imprint of Bardeen potentials on galaxy clustering
• Bispectrum constraints on Primordial non-Gaussianities with the eBOSS DR16 quasars
• Super sample covariance and the volume scaling of galaxy survey covariance matrices
• An empirical nonlinear power spectrum overdensity-response