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Yankelevich, Victoria and Porciani, Cristiano (2019). Cosmological information in the redshift-space bispectrum. Mon. Not. Roy. Astron. Soc., 483 (2). S. 2078 - 2100. OXFORD: OXFORD UNIV PRESS. ISSN 1365-2966

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Abstract

We use the Fisher-matrix formalism to investigate whether the galaxy bispectrum in redshift space, B, contains additional cosmological information with respect to the power spectrum, P. We focus on a Euclid-like survey and consider cosmological models dominated by dark energy and cold dark matter with Gaussian primordial perturbations. After discussing the phenomenology of redshift-space distortions for the bispectrum, we derive an expression for the cross-covariance between B and P at leading order in perturbation theory. Our equation generalizes previous results that did not consider binning in the orientation of wavevector triangles with respect to the line of sight. By considering Fourier modes with wavenumber k < 0.15 h Mpc(-1), we find that B and P set similar constraints on the cosmological parameters. Generally, error bars moderately improve when the two probes are combined together. For instance, the joint 68.3 per cent credible region for the parameters that describe a dynamical dark-energy equation of state shrinks by a factor of 2.6 with respect to only using the power spectrum. Regrettably, this improvement is cancelled out when the clustering analysis is combined with priors based on current studies of the cosmic microwave background. In this case, combining B and P does not give any appreciable benefit other than allowing a precise determination of galaxy bias. Finally, we discuss how results depend on the binning strategy for the clustering statistics as well as on the maximum wavenumber. We also show that only considering the bispectrum monopole leads to a significant loss of information.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Yankelevich, Victoria UNSPECIFIED UNSPECIFIED UNSPECIFIED Porciani, Cristiano UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-157189
DOI:	10.1093/mnras/sty3143
Journal or Publication Title:	Mon. Not. Roy. Astron. Soc.
Volume:	483
Number:	2
Page Range:	S. 2078 - 2100
Date:	2019
Publisher:	OXFORD UNIV PRESS
Place of Publication:	OXFORD
ISSN:	1365-2966
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language 3-POINT CORRELATION-FUNCTION; LARGE-SCALE STRUCTURE; POWER-SPECTRUM ANALYSIS; COVARIANCE-MATRIX; BIAS; GALAXIES; MODEL; DISTORTIONS; PREDICTIONS; PARAMETER Multiple languages Astronomy & Astrophysics Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/15718