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 -