Redshift-space distortions, pairwise velocities and nonlinearities

By R. Scoccimarro. 2004

442 citations recorded by the source corpus.

We derive the exact relationship, including all nonlinearities, between real-space and redshift-space two-point statistics through the pairwise velocity distribution function. We show using numerical simulations that the pairwise velocity probability distribution function is strongly non-Gaussian at all scales and explain why this is so. We caution that a commonly used ansatz to model the redshift-space power spectrum gives rise to an unphysical distribution of pairwise velocities, and show that it is in general impossible to derive the distribution from measurements of redshift-space clustering. Methods that claim to do this obtain instead something else, whose properties we derive. We provide a general derivation of the large-scale limit of the redshift-space power spectrum and show that it differs from the Kaiser formula by terms that depend on Gaussian and non-Gaussian contributions to the velocity dispersion of large-scale flows. We also show that the large-scale evolution of velocity fields is not well described by linear theory and discuss how this impacts the redshift-space power spectrum. Finally, we stress that using the monopole of the redshift-space power as an indicator of the real-space power spectrum shape can lead to systematic effects in the determination of cosmological parameters; nevertheless a simple procedure is able tomore » recover the large-scale real-space power spectrum rather well.« less

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/c80215d37dbfb6a9fc821d5ae28b71e4f9531d6b

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Citations in the corpus

Simultaneous constraints on the growth of structure and cosmic expansion from the multipole power spectra of the SDSS DR7 LRG sample (2013, background): “…function in redshift space on the basis of perturbative approaches (Matsubara 2008c,b, 2011d, 2013a; Nishimichi & Taruya 2011; Okumura et al. 2012b,a; Reid & White 2011; Scoccimarro 2004a; Seljak & McDonald 2011; Taruya et al. 2009c, 2010d, 2013a; Vlah et al. 2012b, 2013a; Wang et al. 2013).”
The 6dF Galaxy Survey: z \approx 0 measurement of the growth rate and sigma_8 (2012, methodology): “We have modelled the 2D correlation function with a simple streaming model and a more advanced approach suggested by Scoccimarro (2004) combined with the N-body calibrated results from Jennings, Baugh & Pascoli (2011a).”
The bispectrum of galaxies from high-redshift galaxy surveys: Primordial non-Gaussianity and non-linear galaxy bias (2007, background): “Further progress is required particularly for understanding redshift distortions (Scoccimarro 2004).”
Baryonic Acoustic Oscillations in Simulated Galaxy Redshift Surveys (2005, background): “…al. 1999), such as can result from nonlinear growth, nonlinear bias (Kaiser 1987; Coles 1993; Scherrer & Weinberg 1998; Dekel & Lahav 1999; Coles et al. 1999; Seljak 2000; White 2001) or nonlinear redshift distortions (Hamilton 1998; Hatton & Cole 1998; Seljak 2001; White 2001; Scoccimarro 2004).”
The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: cosmological analysis of the DR12 galaxy sample (2016, background): “…theory description of RSD is three decades old (Kaiser 1987), but progress on high-precision RSD constraints has been slow because a variety of non-linear effects influence RSD signals even out to very large scales (Cole, Fisher, & Weinberg 1994; Scoccimarro 2004; Tinker, Weinberg, & Zheng 2006).”
The clustering of the SDSS-IV extended Baryon Oscillation Spectroscopic Survey DR14 quasar sample: measurement of the growth rate of structure from the anisotropic correlation function between redshift 0.8 and 2.2 (2018, background): “This work was extended by Scoccimarro (2004) and Reid & White (2011), leading to the following real to redshift space mapping encoded by the probability P that a pair of objects with real-space LOS separation r‖ will be observed with redshift space LOS separation s‖ such that pair conservation…”
The VIMOS Public Extragalactic Redshift Survey (VIPERS): The growth of structure at $0.5 < z < 1.2$ from redshift-space distortions in the clustering of the PDR-2 final sample (2016, methodology): “A further method often used in the literature is that of smoothing the observed redshift distribution with a Gaussian kernel (as for instance in the parallel papers by Rota et al. 2016 and Wilson et al. 2017).”
Beyond the Cosmological Standard Model (2014, unknown): “Although the picture is more complicated in reality, it is a good approximation to decompose the redshift space power spectrum in terms of three isotropic power spectra relating the galaxy overdensity δg and peculiar velocities v: the galaxy power spectrum Pgg(k), the velocity power spectrum Pvv(k) ”
Towards an accurate model of the redshift-space clustering of haloes in the quasi-linear regime (2011, background): “15), the corresponding pairwise velocity PDF is non-Gaussian; however, near its peak it can be approximated by a Gaussian centred on µv12(r) (Scoccimarro 2004).”
Gravity and Large-Scale Nonlocal Bias (2012, background): “However, since the velocity power spectrum is suppressed compared to the density at small scales [80], the dependence is not very strong, particularly because, in G2, the coupling to smallscale modes requires wave vectors to be anti-colinear in which case their contribution to G2 vanishes.”
Large-Scale Anisotropic Correlation Function of SDSS Luminous Red Galaxies (2007, methodology): “We also do not use the data along the line-of-sight, namely, s⊥ 10 h −1 Mpc, because the line-of-sight components of the 2PCF are noisy (Bernstein 1994) and furthermore deviate from Kaiser’s formula even on large scales (Scoccimarro 2004).”
Clustering of luminous red galaxies – IV. Baryon acoustic peak in the line-of-sight direction and a direct measurement of H(z) (2008, background): “It is not entirely clear to us how significant the difference is, but it should be noted that non-linear redshift space distortions have yet to be properly explored and modeled in the LOS direction Scoccimarro (2004).”