Cosmology and the Bispectrum

By E. Sefusatti, Martín Crocce, Sebastian Pueblas, R. Scoccimarro. 2006

201 citations recorded by the source corpus.

The present spatial distribution of galaxies in the Universe is non-Gaussian, with 40% skewness in 50 h{sup -1} Mpc spheres, and remarkably little is known about the information encoded in it about cosmological parameters beyond the power spectrum. In this work they present an attempt to bridge this gap by studying the bispectrum, paying particular attention to a joint analysis with the power spectrum and their combination with CMB data. They address the covariance properties of the power spectrum and bispectrum including the effects of beat coupling that lead to interesting cross-correlations, and discuss how baryon acoustic oscillations break degeneracies. They show that the bispectrum has significant information on cosmological parameters well beyond its power in constraining galaxy bias, and when combined with the power spectrum is more complementary than combining power spectra of different samples of galaxies, since non-Gaussianity provides a somewhat different direction in parameter space. In the framework of flat cosmological models they show that most of the improvement of adding bispectrum information corresponds to parameters related to the amplitude and effective spectral index of perturbations, which can be improved by almost a factor of two. Moreover, they demonstrate that the expected statistical uncertainties in {sigma}s ofmore » a few percent are robust to relaxing the dark energy beyond a cosmological constant.« less

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/3766129d4c07426abac7e18a7f13a4e5f8c8e31e

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Citations in the corpus

The impact of non‐Gaussian errors on weak lensing surveys (2008, background): “In this section we derive the beat-coupling contribution tothe power spectrum covariance in more detail (also see Hamilton et al. 2006 and Sefusatti et al. 2006).”
Primordial Non-Gaussianity and Bispectrum Measurements in the Cosmic Microwave Background and Large-Scale Structure (2010, background): “The issue of bispectrum covariance has been studied in [165, 184, 185, 192].”
The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: RSD measurement from the power spectrum and bispectrum of the DR12 BOSS galaxies (2016, background): “…are Gaussian-distributed (which should be true at least at sufficiently large scales) the effective Fourier volume is reduced by a symmetry factor of 6 for equilateral, and 2 for isosceles, respect to the scalene triangles of similar scales (Scoccimarro et al. 1998; Sefusatti et al. 2006).”
The bispectrum of galaxies from high-redshift galaxy surveys: Primordial non-Gaussianity and non-linear galaxy bias (2007, methodology): “Moreover, it has been shown that the galaxy bispectrum contains additional cosmological information that is not present in the power spectrum (Sefusatti & Scoccimarro 2005; Sefusatti et al. 2006).”
The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey:a large sample of mock galaxy catalogues (2012, background): “…rescaling of the linear Gaussian covariance, must deal with non-linear evolution, shotnoise, redshift space distortions, and the complex mapping between galaxies and matter (Hamilton, Rimes and Scoccimarro 2006; Sefusatti et al. 2006; Pope and Szapudi 2008; de Putter 2012; Sefussati et al 2012).”
Gravity and Large-Scale Nonlocal Bias (2012, background): “This is important because this systematic error would otherwise affect the determination of cosmological parameters from a bispectrum analysis (see [85]), particularly for luminous galaxies (such as LRGs in SDSS) that populate high-mass halos.”