TY - JOUR

T1 - Einstein's signature in cosmological large-scale structure

AU - Bruni, Marco

AU - Hidalgo, Juan Carlos

AU - Wands, David

N1 - copyright 2014. The American Astronomical Society

PY - 2014/10/10

Y1 - 2014/10/10

N2 - We show how the nonlinearity of general relativity generates a characteristic nonGaussian signal in cosmological large-scale structure that we calculate at all perturbative orders in a large-scale limit. Newtonian gravity and general relativity provide complementary theoretical frameworks for modeling large-scale structure in ΛCDM cosmology; a relativistic approach is essential to determine initial conditions, which can then be used in Newtonian simulations studying the nonlinear evolution of the matter density. Most inflationary models in the very early universe predict an almost Gaussian distribution for the primordial metric perturbation, ζ. However, we argue that it is the Ricci curvature of comoving-orthogonal spatial hypersurfaces, R, that drives structure formation at large scales. We show how the nonlinear relation between the spatial curvature, R, and the metric perturbation, ζ, translates into a specific nonGaussian contribution to the initial comoving matter density that we calculate for the simple case of an initially Gaussian ζ. Our analysis shows the nonlinear signature of Einstein's gravity in large-scale structure.

AB - We show how the nonlinearity of general relativity generates a characteristic nonGaussian signal in cosmological large-scale structure that we calculate at all perturbative orders in a large-scale limit. Newtonian gravity and general relativity provide complementary theoretical frameworks for modeling large-scale structure in ΛCDM cosmology; a relativistic approach is essential to determine initial conditions, which can then be used in Newtonian simulations studying the nonlinear evolution of the matter density. Most inflationary models in the very early universe predict an almost Gaussian distribution for the primordial metric perturbation, ζ. However, we argue that it is the Ricci curvature of comoving-orthogonal spatial hypersurfaces, R, that drives structure formation at large scales. We show how the nonlinear relation between the spatial curvature, R, and the metric perturbation, ζ, translates into a specific nonGaussian contribution to the initial comoving matter density that we calculate for the simple case of an initially Gaussian ζ. Our analysis shows the nonlinear signature of Einstein's gravity in large-scale structure.

KW - dark matter

KW - large-scale structure of universe

KW - RCUK

KW - STFC

KW - ST/K00090X/1 and ST/L005573/1

UR - http://www.scopus.com/inward/record.url?scp=84907543036&partnerID=8YFLogxK

U2 - 10.1088/2041-8205/794/1/L11

DO - 10.1088/2041-8205/794/1/L11

M3 - Article

AN - SCOPUS:84907543036

SN - 2041-8205

VL - 794

SP - L11

JO - Astrophysical Journal Letters

JF - Astrophysical Journal Letters

IS - 1

M1 - L11

ER -