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We calculate the dark matter halo correlation function in redshift space using the Gaussian streaming model (GSM). To determine the scale dependent functions entering the streaming model we use local Lagrangian bias together with…

Cosmology and Nongalactic Astrophysics · Physics 2016-12-28 Michael Kopp , Cora Uhlemann , Ixandra Achitouv

We describe the results of a simulation of collisionless cold dark matter in a LambdaCDM universe to examine the properties of objects collapsing at high redshift (z=10). We analyze the halos that form at these early times in this…

Astrophysics · Physics 2009-10-31 Hannah Jang-Condell , Lars Hernquist

The set-up of the initial conditions in cosmological N-body simulations is usually implemented by rescaling the desired low-redshift linear power spectrum to the required starting redshift consistently with the Newtonian evolution of the…

Cosmology and Nongalactic Astrophysics · Physics 2017-01-18 Matteo Zennaro , Julien Bel , Francisco Villaescusa-Navarro , Carmelita Carbone , Emiliano Sefusatti , Luigi Guzzo

We present a new formulation of Lagrangian perturbation theory which allows accurate predictions of the real- and redshift-space correlation functions of the mass field and dark matter halos. Our formulation involves a non-perturbative…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 Jordan Carlson , Beth Reid , Martin White

Dark matter haloes form from small perturbations to the almost homogeneous density field of the early universe. Although it is known how large these initial perturbations must be to form haloes, it is rather poorly understood how to predict…

Cosmology and Nongalactic Astrophysics · Physics 2024-02-22 Daniel López-Cano , Jens Stücker , Marcos Pellejero Ibañez , Raúl E. Angulo , Daniel Franco-Barranco

At early times dark matter has a thermal velocity dispersion of unknown amplitude which, for warm dark matter models, can influence the formation of nonlinear structure on observable scales. We propose a new scheme to simulate cosmologies…

Cosmology and Nongalactic Astrophysics · Physics 2020-06-10 Jens Stücker , Oliver Hahn , Raul E. Angulo , Simon D. M. White

Relativistic corrections to the evolution of structure can be used to test general relativity on cosmological scales. They are also a well-known systematic contamination in the search for a primordial non-Gaussian signal. We present a…

Cosmology and Nongalactic Astrophysics · Physics 2023-08-28 J. Adamek , J. Calles , T. Montandon , J. Noreña , C. Stahl

We present a method to construct semi-numerical ``simulations'', which can efficiently generate realizations of halo distributions and ionization maps at high redshifts. Our procedure combines an excursion-set approach with first-order…

Astrophysics · Physics 2009-11-13 Andrei Mesinger , Steven Furlanetto

Using high--resolution N--body simulations, we test two theoretical models, based either on spherical or on ellipsoidal collapse model, for the higher--order moments of the dark matter halo distribution in CDM models. We find that a…

Astrophysics · Physics 2009-11-07 R. Casas-Miranda , H. J. Mo , G. Boerner

Generating pre-initial conditions (or particle loads) is the very first step to set up a cosmological N-body simulation. In this work, we revisit the numerical convergence of pre-initial conditions on dark matter halo properties using a set…

Cosmology and Nongalactic Astrophysics · Physics 2022-02-08 Tianchi Zhang , Shihong Liao , Ming Li , Jiajun Zhang

In this work we present cosmological N-body simulations of the Local Universe with initial conditions constrained by the Two-Micron Redshift Survey (2MRS) within a cubic volume of 180 Mpc/h side-length centred at the Local Group. We use a…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Steffen Heß , Francisco-Shu Kitaura , Stefan Gottloeber

We present a new method to calculate formation of cosmological structure in the Newtonian limit. The method is based on Lagrangian perturbation theory plus two key theoretical extensions. One advance involves identifying and fixing a…

Cosmology and Nongalactic Astrophysics · Physics 2014-12-15 Sharvari Nadkarni-Ghosh , David F. Chernoff

Accurate modeling of nonlinearities in the galaxy bispectrum, the Fourier transform of the galaxy three-point correlation function, is essential to fully exploit it as a cosmological probe. In this paper, we present numerical and…

Cosmology and Nongalactic Astrophysics · Physics 2015-12-02 Nuala McCullagh , Donghui Jeong , Alexander S. Szalay

We train a machine learning algorithm to learn cosmological structure formation from N-body simulations. The algorithm infers the relationship between the initial conditions and the final dark matter haloes, without the need to introduce…

Cosmology and Nongalactic Astrophysics · Physics 2018-07-02 Luisa Lucie-Smith , Hiranya V. Peiris , Andrew Pontzen , Michelle Lochner

We use two cosmological simulations of structure formation in the LambdaCDM scenario to study the evolutionary histories of dark-matter haloes and to characterize the Lagrangian regions from which they form. We focus on haloes identified at…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-19 Mikolaj Borzyszkowski , Aaron D. Ludlow , Cristiano Porciani

The properties of the matter density field in the initial conditions have a decisive impact on the features of the large-scale structure of the Universe as observed today. These need to be studied via $N$-body simulations, which are…

Cosmology and Nongalactic Astrophysics · Physics 2023-06-21 Jazhiel Chacón , Isidro Gómez-Vargas , Ricardo Menchaca Méndez , José Alberto Vázquez

Current models of galaxy formation applied to understanding the large-scale structure of the universe have two parts. The first is an accurate solution of the equations of motion for the dark matter due to gravitational clustering. The…

Astrophysics · Physics 2009-11-06 Roman Scoccimarro , Ravi K. Sheth

Lagrangian algorithms to simulate the evolution of cold dark matter (CDM) are invaluable tools to generate large suites of mock halo catalogues. In this paper, we first show that the main limitation of current semi-analytical schemes to…

Cosmology and Nongalactic Astrophysics · Physics 2021-06-04 Federico Tosone , Mark C. Neyrinck , Benjamin R. Granett , Luigi Guzzo , Nicola Vittorio

In Part I of this series, we introduced the Spherical Collapse (SC) approximation in Lagrangian space as a way of estimating the cumulants $\xi_J$ of density fluctuations in cosmological Perturbation Theory (PT). Within this approximation,…

Astrophysics · Physics 2009-10-30 Enrique Gaztanaga , Pablo Fosalba

In previous works we proposed the Reverse Zeldovich Approximation (RZA) method, which can be used to estimate the cosmological initial conditions underlying the galaxy distribution in the Local Universe using peculiar velocity data. In this…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Timur Doumler , Stefan Gottloeber , Yehuda Hoffman , Helene Courtois