Disentangling non-Gaussianity, bias, and general relativistic effects in the galaxy distribution

2011/06/30 by Marco Bruni, Robert Crittenden, Kazuya Koyama +4 · 8 citations
Mathematics · Physics and Astronomy · #Astrophysics #Cosmic microwave background #Cosmology and Gravitation Theories #Galaxies: Formation, Evolution, Phenomena #Galaxy #Gamma-ray bursts and supernovae #Gauge (firearms) #Mathematics #Non-Gaussianity #Observable #Physics #Quantum mechanics #Redshift #Spectral density #Spectral line #Statistical physics #Statistics #astro-ph.CO #gr-qc #hep-ph #hep-th

paper · pdf · doi:10.1103/physrevd.85.041301

published as Phys.Rev. D85 (2012) 041301 · 5 pages, 2 figures, published version

openalex publication_date 2012/02/08 · arxiv created 2012/03/07 · arxiv updated 2013/05/29 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05

Abstract

Local non-Gaussianity, parametrized by f_NL, introduces a scale-dependent bias that is strongest at large scales, precisely where general relativistic (GR) effects also become significant. With future data, it should be possible to constrain f_NL=O(1) with high redshift surveys. GR corrections to the power spectrum and ambiguities in the gauge used to define bias introduce effects similar to f_NL=O(1), so it is essential to disentangle these effects. For the first time in studies of primordial non-Gaussianity, we include the consistent GR calculation of galaxy power spectra, highlighting the importance of a proper definition of bias. We present observable power spectra with and without GR corrections, showing that an incorrect definition of bias can mimic non-Gaussianity. However, these effects can be distinguished by their different redshift and scale dependence, so as to extract the true primordial non-Gaussianity.

Cited by

• General relativistic cosmological N-body simulations. Part I. Time integration
• Relativistic corrections and non-Gaussianity in radio continuum surveys
• Non-Gaussianity and excursion set theory: Halo bias
• Degeneracy between primordial non-Gaussianity and interaction in the dark sector
• Dark energy homogeneity in general relativity: Are we applying it correctly?
• Cosmic degeneracies III: N-body simulations of interacting dark energy with non-Gaussian initial conditions
• Lensing and time-delay contributions to galaxy correlations
• Practical approach to cosmological perturbations in modified gravity

Related

• Galaxy Bias and Primordial Non-Gaussianity
• Primordial non-Gaussianity -- the effects of relativistic and wide-angle corrections to the power spectrum
• Unbiased analysis of primordial non-Gaussianity: the multipoles of the full relativistic power spectrum
• Post-inflationary Contamination of Local Primordial Non-Gaussianity in Galaxy Power Spectra
• Local Primordial non-Gaussian Bias from Time Evolution