Universität zu Köln

Kuruvilla, Joseph ORCID: 0000-0002-0088-5182 and Porciani, Cristiano (2018). On the streaming model for redshift-space distortions. Mon. Not. Roy. Astron. Soc., 479 (2). S. 2256 - 2277. OXFORD: OXFORD UNIV PRESS. ISSN 1365-2966

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Abstract

The streaming model describes the mapping between real and redshift space for 2-point clustering statistics. Its key element is the probability density function (PDF) of line-of-sight pairwise peculiar velocities. Following a kinetic-theory approach, we derive the fundamental equations of the streaming model for ordered and unordered pairs. In the first case, we recover the classic equation while we demonstrate that modifications are necessary for unordered pairs. We then discuss several statistical properties of the pairwise velocities for DM particles and haloes by using a suite of high-resolution N-body simulations. We test the often used Gaussian ansatz for the PDF of pairwise velocities and discuss its limitations. Finally, we introduce a mixture of Gaussians which is known in statistics as the generalized hyperbolic distribution and show that it provides an accurate fit to the PDF. Once inserted in the streaming equation, the fit yields an excellent description of redshift-space correlations at all scales that vastly outperforms the Gaussian and exponential approximations. Using a principal-component analysis, we reduce the complexity of our model for large redshift-space separations. Our results increase the robustness of studies of anisotropic galaxy clustering and are useful for extending them towards smaller scales in order to test theories of gravity and interacting dark-energy models.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Kuruvilla, Joseph UNSPECIFIED orcid.org/0000-0002-0088-5182 UNSPECIFIED Porciani, Cristiano UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-175726
DOI:	10.1093/mnras/sty1654
Journal or Publication Title:	Mon. Not. Roy. Astron. Soc.
Volume:	479
Number:	2
Page Range:	S. 2256 - 2277
Date:	2018
Publisher:	OXFORD UNIV PRESS
Place of Publication:	OXFORD
ISSN:	1365-2966
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language COLD DARK-MATTER; OSCILLATION SPECTROSCOPIC SURVEY; DIGITAL SKY SURVEY; PAIRWISE VELOCITY DISPERSION; HALO OCCUPATION DISTRIBUTION; LARGE-SCALE STRUCTURE; MEAN MASS DENSITY; PECULIAR VELOCITIES; GROWTH-RATE; POWER SPECTRUM Multiple languages Astronomy & Astrophysics Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/17572