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We study the mass, velocity dispersion, and anisotropy profiles of $\Lambda$CDM halos using a suite of N-body simulations of unprecedented numerical resolution (the {\it Aquarius Project}). Our analysis confirms a number of results claimed…

Variational methods are attractive for computing Bayesian inference for highly parametrized models and large datasets where exact inference is impractical. They approximate a target distribution - either the posterior or an augmented…

Computation · Statistics 2019-11-21 Michael Stanley Smith , Ruben Loaiza-Maya , David J. Nott

We discuss the extension to redshift space of a rescaling algorithm, designed to alter the effective cosmology of a pre-existing simulated particle distribution or catalogue of dark matter haloes. The rescaling approach was initially…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-25 Alexander Mead , John Peacock

We use a set of numerical N-body simulations to study the large-scale behavior of the reduced bispectrum of dark matter and compare the results with the second-order perturbation theory and the halo models for different halo mass functions.…

Cosmology and Nongalactic Astrophysics · Physics 2011-02-11 Hong Guo , Y. P. Jing

We present a new methodology to generate mock halo or galaxy catalogues, which have accurate clustering properties, nearly indistinguishable from full $N$-body solutions, in terms of the one-point, two-point, and three-point statistics. In…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-08 Chia-Hsun Chuang , Francisco-Shu Kitaura , Francisco Prada , Cheng Zhao , Gustavo Yepes

We provide a simple, unified approach to describing the impact of super-sample covariance, or beat coupling, on power spectrum estimation in a finite-volume survey. For a wide range of survey volumes, the sample variance that arises from…

Cosmology and Nongalactic Astrophysics · Physics 2014-01-06 Masahiro Takada , Wayne Hu

We evaluate the covariance matrix of the matter power spectrum using perturbation theory up to dominant terms at 1-loop order and compare it to numerical simulations. We decompose the covariance matrix into the disconnected (Gaussian) part,…

Cosmology and Nongalactic Astrophysics · Physics 2017-01-18 Irshad Mohammed , Uros Seljak , Zvonimir Vlah

We present a general method to compute the nonlinear matter power spectrum for dark energy and modified gravity scenarios with percent-level accuracy. By adopting the halo model and nonlinear perturbation theory, we predict the reaction of…

Cosmology and Nongalactic Astrophysics · Physics 2019-07-16 Matteo Cataneo , Lucas Lombriser , Catherine Heymans , Alexander Mead , Alexandre Barreira , Sownak Bose , Baojiu Li

We use analytic covariance matrices to carry out a full-shape analysis of the galaxy power spectrum multipoles from the Baryon Oscillation Spectroscopic Survey (BOSS). We obtain parameter estimates that agree well with those based on the…

Cosmology and Nongalactic Astrophysics · Physics 2020-12-29 Digvijay Wadekar , Mikhail M. Ivanov , Roman Scoccimarro

Super sample covariance (SSC) is important when estimating covariance matrices using a set of mock catalogues for galaxy surveys. If the underlying cosmological simulations do not include the variation in background parameters appropriate…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-05 Greg Schreiner , Alex Krolewski , Shahab Joudaki , Will J. Percival

We present results from a study of bias and its evolution for galaxy-size halos in a large, high-resolution simulation of a LCDM model. We consider the evolution of bias estimated using two-point correlation function (b_xi), power spectrum…

Astrophysics · Physics 2009-10-31 Andrey Kravtsov , Anatoly Klypin

We use available measurements to estimate the unknown parameters (variance, smoothness parameter, and covariance length) of a covariance function by maximizing the joint Gaussian log-likelihood function. To overcome cubic complexity in the…

Computation · Statistics 2018-09-13 Alexander Litvinenko , Ying Sun , Marc G. Genton , David Keyes

We use the universal mass accretion history recently reported for simulations of halo formation in the cold dark matter model (CDM) to analyze the formation and growth of a single halo. We derive the time-dependent density profile three…

Astrophysics · Physics 2007-05-23 Marcelo A. Alvarez , Kyungjin Ahn , Paul R. Shapiro

Using hydrodynamical simulations, we study how well the underlying gravitational potential of a galaxy cluster can be modelled dynamically with different types of tracers. In order to segregate different systematics and the effects of…

Astrophysics of Galaxies · Physics 2021-06-30 Qingyang Li , Jiaxin Han , Wenting Wang , Weiguang Cui , Zhaozhou Li , Xiaohu Yang

We examined the reliability of estimates of pseudoisothermal, Burkert and NFW dark halo parameters for the methods based on the mass-modelling of the rotation curves.To do it we constructed the $\chi^2$ maps for the grid of the dark matter…

Astrophysics of Galaxies · Physics 2016-08-24 Anna Saburova , Anastasia Kasparova , Ivan Katkov

On the smallest scales, three-dimensional large-scale structure surveys contain a wealth of cosmological information which cannot be trivially extracted due to the non-linear dynamical evolution of the density field. Lagrangian perturbation…

Cosmology and Nongalactic Astrophysics · Physics 2015-08-05 Florent Leclercq , Jens Jasche , Héctor Gil-Marín , Benjamin Wandelt

To maximize the amount of information extracted from cosmological datasets, simulations that accurately represent these observations are necessary. However, traditional simulations that evolve particles under gravity by estimating…

We study the evolution of matter density perturbations in Galileon cosmology where the late-time cosmic acceleration can be realized by a field kinetic energy. We obtain full perturbation equations at linear order in the presence of five…

Cosmology and Nongalactic Astrophysics · Physics 2011-02-23 Antonio De Felice , Ryotaro Kase , Shinji Tsujikawa

We present a method to estimate non-Gaussian power spectrum covariance matrices by directly measuring the response of the small-scale power spectrum to long-wavelength perturbations via bispectrum and trispectrum estimators. Specifically,…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-21 Samuel Goldstein , Kendrick M. Smith , Utkarsh Giri , Moritz Münchmeyer

Subhalos play a crucial role in accurately modeling galaxy formation and galaxy-based cosmological probes within the highly nonlinear, virialized regime. However, numerical convergence of subhalo evolution is difficult to achieve,…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-16 Kun Xu