%0 Journal Article
%T Hunting high and low: disentangling primordial and late-time non-Gaussianity with cosmic densities in spheres
%+ Utrecht University [Utrecht]
%+ Institut d'Astrophysique de Paris (IAP)
%+ Korea Institute for Advanced Study (KIAS)
%+ Kavli Institute for the Physics and Mathematics of the Universe [Tokyo] (Kavli IPMU)
%+ JST-CREST
%+ Canadian Institute for Theoretical Astrophysics (CITA)
%+ Institut de Physique Théorique - UMR CNRS 3681 (IPHT)
%A Uhlemann, C.
%A Pajer, E.
%A Pichon, C.
%A Nishimichi, T.
%A Codis, S.
%A Bernardeau, F.
%< avec comité de lecture
%@ 0035-8711
%J Monthly Notices of the Royal Astronomical Society
%I Oxford University Press (OUP): Policy P - Oxford Open Option A
%V 474
%N 3
%P 2853 - 2870
%8 2018-03-01
%D 2018
%R 10.1093/mnras/stx2623
%K cosmology: theory
%K large-scale structure of Universe
%K methods: analytical
%K numerical
%Z Physics [physics]
%Z Sciences of the Universe [physics]Journal articles
%X Non-Gaussianities of dynamical origin are disentangled from primordial ones using the formalism of large deviation statistics with spherical collapse dynamics. This is achieved by relying on accurate analytical predictions for the one-point probability distribution function (PDF) and the two-point clustering of spherically-averaged cosmic densities (sphere bias).Sphere bias extends the idea of halo bias to intermediate density environments and voids as underdense regions. In the presence of primordial non-Gaussianity, sphere bias displays a strong scale dependence relevant for both high and low density regions, which is predicted analytically. The statistics of densities in spheres are built to model primordial non-Gaussianityvia an initial skewness with a scale-dependence that depends on the bispectrum of the underlying model. The analytical formulas with the measured nonlinear dark matter variance as iNon-Gaussianities of dynamical origin are disentangled from primordial ones using the formalism of large deviation statistics with spherical collapse dynamics. This is achieved by relying on accurate analytical predictions for the one-point probability distribution function (PDF) and the two-point clustering of spherically-averaged cosmic densities (sphere bias).Sphere bias extends the idea of halo bias to intermediate density environments and voids as underdense regions. In the presence of primordial non-Gaussianity, sphere bias displays a strong scale dependence relevant for both high and low density regions, which is predicted analytically. The statistics of densities in spheres are built to model primordial non-Gaussianity via an initial skewness with a scale-dependence that depends on the bispectrum of the underlying model. The analytical formulas with the measured nonlinear dark matter variance as input are successfully tested against numerical simulations. For local non-Gaussianity with a range from $f_{NL}$ $=$ $−$100 to $+$100 they are found to agree within 2% or better for densities $\rho$ $\in$ [0.5, 3] in spheres of radius 15 Mpc/$h$ down to $z$ = 0.35. The validity of the large deviation statistics formalism is thereby established for all observationally relevant local-type departures from perfectly Gaussian initial conditions. The corresponding estimators for the amplitude of the nonlinear variance $\sigma _8$ and primordial skewness $f_{NL}$ are validated using a fiducial joint maximum likelihood experiment. The influence of observational effects and the prospects for a future detection of primordial non-Gaussianity from joint one- and two-point densities-in-spheres statistics are discussed.
%G English
%2 https://cea.hal.science/cea-01677174/document
%2 https://cea.hal.science/cea-01677174/file/stx2623.pdf
%L cea-01677174
%U https://cea.hal.science/cea-01677174
%~ CEA
%~ INSU
%~ CNRS
%~ IAP
%~ DSM-IPHT
%~ CEA-UPSAY
%~ UNIV-PARIS-SACLAY
%~ CEA-UPSAY-SACLAY
%~ CEA-DRF
%~ SORBONNE-UNIVERSITE
%~ SORBONNE-UNIV
%~ SU-SCIENCES
%~ TEST-HALCNRS
%~ SU-TI
%~ ANR
%~ GS-MATHEMATIQUES
%~ GS-PHYSIQUE
%~ ALLIANCE-SU