Beyond the two-point correlation: constraining primordial non-gaussianity with density perturbation moments

Abstract

Constraining primordial non-Gaussianities (PNGs) in the large-scale cosmic structure (LSS) is an important step in understanding properties of the early universe, specifically in distinguishing between different inflationary models. Measuring PNG relies on evaluating the scale-dependent correlations in the density field. New summary statistics beyond the two- and three-point correlation functions in configuration space and their Fourier-space counterparts, the power- and bi-spectrum may provide increased sensitivity. We introduce a new method for extracting the PNG signal imprinted on the LSS by using the first three Gaussian moments of the normalized correlation in density perturbations, evaluated at varying distance scales. We aim to assess this method's sensitivity to local PNG, parameterized by $f_{\mathrm{NL}}$. We perform spherical convolutions at a range of scales on dark matter halo simulations to measure the scale-dependent correlations in the density field. From these, we compute the first three moments and compare them to a model expectation vector, parameterized to the second power in $f_{\mathrm{NL}}$. Our method provides about 21% improvement in sensitivity to $f_{\mathrm{NL}}$ with respect to using the two point correlation function alone. Notably, we find that the second moment alone carries nearly as much constraining power as the mean, highlighting the potential of higher-order statistics. Given its simplicity and efficiency, this framework is well-suited for application to current and upcoming large-scale surveys such as DESI.

10 pages, 9 figures, to be submitted to Astronomy & Astrophysics

References in corpus (22)

• emcee: The MCMC Hammer
• Non-Gaussian features of primordial fluctuations in single field inflationary models
• Acoustic Signatures in the Primary Microwave Background Bispectrum
• The imprints of primordial non-gaussianities on large-scale structure: scale dependent bias and abundance of virialized objects
• DESI DR2 Results II: Measurements of Baryon Acoustic Oscillations and Cosmological Constraints
• DESI 2024 III: Baryon Acoustic Oscillations from Galaxies and Quasars
• FastPM: a new scheme for fast simulations of dark matter and halos
• The Clustering of Galaxies in SDSS-III DR9 Baryon Oscillation Spectroscopic Survey: Constraints on Primordial Non-Gaussianity
• The (not so) squeezed limit of the primordial 3-point function
• Redshift-weighted constraints on primordial non-Gaussianity from the clustering of the eBOSS DR14 quasars in Fourier space
• On the impact of galaxy bias uncertainties on primordial non-Gaussianity constraints
• Primordial non-Gaussianity from the Completed SDSS-IV extended Baryon Oscillation Spectroscopic Survey I: Catalogue Preparation and Systematic Mitigation
• Optimising primordial non-Gaussianity measurements from galaxy surveys
• Fundamental limits on constraining primordial non-Gaussianity
• PNG-UNITsims: Halo clustering response to primordial non-Gaussianities as a function of mass
• Constraining Primordial Non-Gaussianity with Moments of the Large Scale Density Field
• The DESI One-Percent Survey: Modelling the clustering and halo occupation of all four DESI tracers with Uchuu
• Primordial non-Gaussianity with Angular correlation function: Integral constraint and validation for DES
• ConKer: evaluating isotropic correlations of arbitrary order
• Capturing primordial non-Gaussian signatures in the late Universe by multi-scale extrema of the cosmic log-density field
• Bispectrum constraints on Primordial non-Gaussianities with the eBOSS DR16 quasars
• Constraining primordial non-Gaussianity from the large scale structure two-point and three-point correlation functions