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Galaxy redshift surveys encode a wealth of information generated by nonlinear gravitational evolution, galaxy bias, and redshift-space distortions, only part of which is accessible through standard two-point statistics. Motivated by the…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-29 Davide Bianchi

We present a detailed analysis of the two-point correlation function, from the 2dF Galaxy Redshift Survey (2dFGRS). We estimate the redshift-space correlation function, xi(s), from which we measure the redshift-space clustering length,…

We study the peculiar velocities of density peaks in the presence of primordial non-Gaussianity. Rare, high density peaks in the initial density field can be identified with tracers such as galaxies and clusters in the evolved matter…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-21 Fabian Schmidt

In a disc galaxy the distribution of azimuthal components of velocity is very skew. In the past this skewness has been modelled by superposed Gaussians. We use dynamical arguments to derive an analytic formula that can be fitted to observed…

Astrophysics of Galaxies · Physics 2015-05-30 Ralph Schoenrich , James Binney

We present the first measurements of clustering in the Sloan Digital Sky Survey (SDSS) galaxy redshift survey. Our sample consists of 29,300 galaxies with redshifts 5,700 km/s < cz < 39,000 km/s, distributed in several long but narrow…

We investigate the use of the cross-correlation between galaxies and galaxy groups to measure redshift-space distortions (RSD) and thus probe the growth rate of cosmological structure. This is compared to the classical approach based on…

Cosmology and Nongalactic Astrophysics · Physics 2016-03-24 Faizan G. Mohammad , Sylvain de la Torre , Davide Bianchi , Luigi Guzzo , John A. Peacock

We perform a comprehensive redshift-space distortion analysis based on cosmic voids in the large-scale distribution of galaxies observed with the Sloan Digital Sky Survey. To this end, we measure multipoles of the void-galaxy…

Cosmology and Nongalactic Astrophysics · Physics 2017-07-12 Nico Hamaus , Marie-Claude Cousinou , Alice Pisani , Marie Aubert , Stéphanie Escoffier , Jochen Weller

We study the effects of peculiar velocities on statistical measures of galaxy clustering. These effects occur when distances to the galaxies are estimated from their redshifts. It is assumed that the clustering pattern results from the…

Astrophysics · Physics 2011-05-23 E. Hivon , F. R. Bouchet , S. Colombi , R. Juszkiewicz

We generalize the well-known mixtures of Gaussians approach to density estimation and the accompanying Expectation--Maximization technique for finding the maximum likelihood parameters of the mixture to the case where each data point…

Methodology · Statistics 2011-08-01 Jo Bovy , David W. Hogg , Sam T. Roweis

We develop a method for probabilistic prediction of extreme value hot-spots in a spatio-temporal framework, tailored to big datasets containing important gaps. In this setting, direct calculation of summaries from data, such as the minimum…

Methodology · Statistics 2020-04-02 Daniela Castro-Camilo , Linda Mhalla , Thomas Opitz

We present a simple method for evaluating the nonlinear biasing function of galaxies from a redshift survey. The nonlinear biasing is characterized by the conditional mean of the galaxy density fluctuation given the underlying mass density…

Astrophysics · Physics 2009-10-31 Yair Sigad , Enzo Branchini , Avishai Dekel

Primordial, non-Gaussian perturbations can generate scale-dependent bias in the galaxy distribution. This in turn will modify correlations between galaxy positions and peculiar velocities at late times, since peculiar velocities reflect the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Yin-Zhe Ma , James E. Taylor , Douglas Scott

We derive an analytic expression for the two-point correlation function in redshift space which (i) is nonlinear; (ii) is valid on the full sky, i.e. the distant-observer limit is not assumed; (iii) can account for the effect of…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-08 Lawrence Dam , Camille Bonvin

We study the probability distribution function (PDF) of relative velocity between two different dark matter halos (i.e. pairwise velocity) with a set of high-resolution cosmological $N$-body simulations. We investigate the pairwise velocity…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-17 Masato Shirasaki , Eric M. Huff , Katarina Markovic , Jason D. Rhodes

We develop a statistical estimator to infer the redshift probability distribution of a photometric sample of galaxies from its angular cross-correlation in redshift bins with an overlapping spectroscopic sample. This estimator is a minimum…

The simplest theory describing large-scale redshift-space distortions (RSD), based on linear theory and distant galaxies, depends on the growth of cosmological structure, suggesting that strong tests of General Relativity can be constructed…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-18 Lado Samushia , Will J. Percival , Alvise Raccanelli

We derive the pairwise peculiar velocity distribution function of dark matter particles applying the dark matter halo approach. Unlike the previous work, we do not assume a Gaussian velocity distribution function of dark matter in a single…

Astrophysics · Physics 2015-06-24 Takeshi Kuwabara , Atsushi Taruya , Yasushi Suto

One of the main problems of observational cosmology is to determine the range in which a reliable measurement of galaxy correlations is possible. This corresponds to determine the shape of the correlation function, its possible evolution…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-18 Francesco Sylos Labini , Daniil Tekhanovich , Yurij V. Baryshev

We have investigated the redshift space distortions in the optically selected Durham/UKST Galaxy Redshift Survey using the 2-point galaxy correlation function perpendicular and parallel to the observer's line of sight. We present results…

Astrophysics · Physics 2009-10-30 A. Ratcliffe , T. Shanks , R. Fong , Q. A. Parker

We provide an analytical description of the galaxy bispectrum covariance and the power spectrum-bispectrum cross-covariance in redshift space that captures the dominant non-Gaussian contributions. The Gaussian prediction for the variance of…

Cosmology and Nongalactic Astrophysics · Physics 2024-03-14 Jacopo Salvalaggio , Lina Castiblanco , Jorge Noreña , Emiliano Sefusatti , Pierluigi Monaco