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We study the growth of large scale structure in two recently proposed non-standard cosmological models: the brane induced gravity model of Dvali, Gabadadze and Porrati (DGP) and the Cardassian models of Freese and Lewis. A general formalism…

Astrophysics · Physics 2009-11-07 T. Multamaki , E. Gaztanaga , M. Manera

We elucidate the importance of the consistent treatment of gravity-model specific non-linearities when estimating the growth of cosmological structures from redshift space distortions (RSD). Within the context of standard perturbation…

Cosmology and Nongalactic Astrophysics · Physics 2017-07-26 Benjamin Bose , Kazuya Koyama , Wojciech A. Hellwing , Gong-Bo Zhao , Hans A. Winther

We present a new and completely general technique for calculating the fine-grained phase-space structure of dark matter throughout the Galactic halo. Our goal is to understand this structure on the scales relevant for direct and indirect…

Astrophysics · Physics 2009-11-13 Mark Vogelsberger , Simon D. M. White , Amina Helmi , Volker Springel

We describe and test a new method for creating initial conditions for cosmological N-body dark matter simulations based on second-order Lagrangian perturbation theory (2lpt). The method can be applied to multi-mass particle distributions…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Adrian Jenkins

We study one of the simplest covariant modified-gravity models based on the Dvali-Gabadadze-Porrati (DGP) brane cosmology, a self-accelerating universe. In this model gravitational leakage into extra dimensions is responsible of late-time…

Astrophysics · Physics 2009-04-08 M. Sadegh Movahed , Marzieh Farhang , Sohrab Rahvar

We present and test a new numerical method to determine second-order Lagrangian displacement fields in the context of modified gravity (MG) theories. We start from the extension of Lagrangian Perturbation Theory to a class of MG models that…

Cosmology and Nongalactic Astrophysics · Physics 2020-03-04 Chiara Moretti , Simone Mozzon , Pierluigi Monaco , Emiliano Munari , Marco Baldi

We study the linear growth of matter perturbations in the DGP model with the growth index $\gamma$ as a function of redshift. At the linear approximation: $\gamma(z)\approx\gamma_0+\gamma_0^\prime z $, we find that, for…

General Relativity and Quantum Cosmology · Physics 2010-05-28 Xiangyun Fu , Puxun Wu , Hongwei Yu

We study the accuracy of several approximate methods for gravitational dynamics in terms of halo power spectrum multipoles and their estimated covariance matrix. We propagate the differences in covariances into parameter constrains related…

We develop a Lagrangian Perturbation Theory (LPT) framework to study the clustering of cold dark matter (CDM) in cosmologies with massive neutrinos. We follow the trajectories of CDM particles with Lagrangian displacements fields up to…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-28 Alejandro Aviles , Arka Banerjee

This work explores the ability of computer vision algorithms to characterise dark matter haloes formed in different models of structure formation. We produce surface mass density maps of the most massive haloes in a suite of eight numerical…

Cosmology and Nongalactic Astrophysics · Physics 2017-04-19 Julian Merten , Quim Llorens , Hans Winther

We use Luminous Red Galaxies from the Sloan Digital Sky Survey II to test the cosmological structure growth in two alternatives to the standard LCDM+GR cosmological model. We compare observed three-dimensional clustering in SDSS DR7 with…

We present a detailed description and validation of our massively-parallel update to the mass-Peak Patch method, a fully predictive initial-space algorithm to quickly generate dark matter halo catalogues in very large cosmological volumes.…

Cosmology and Nongalactic Astrophysics · Physics 2018-12-05 George Stein , Marcelo A. Alvarez , J. Richard Bond

The statistical mechanics of N cold dark matter (CDM) particles interacting via a softened gravitational potential is reviewed in the microcanonical ensemble and mean-field limit. A phase diagram for the system is computed as a function of…

Astrophysics · Physics 2014-10-13 Cathryn M. Trott , Andrew Melatos

Observations on galactic scales seem to be in contradiction with recent high resolution N-body simulations. This so-called cold dark matter (CDM) crisis has been addressed in several ways, ranging from a change in fundamental physics by…

Astrophysics · Physics 2008-11-26 Alexander Knebe , Brett Little , Ranty Islam , Julien Devriendt , Asim Mahmood , Joe Silk

We develop and test an algorithm to rescale a simulated dark-matter particle distribution or halo catalogue from a standard gravity model to that of a modified gravity model. This method is based on that of Angulo & White but with some…

Cosmology and Nongalactic Astrophysics · Physics 2015-08-18 Alexander Mead , John Peacock , Lucas Lombriser , Baojiu Li

We use high resolution N-Body simulations to study the concentration and spin parameters of dark matter haloes in the mass range $10^8\, {\rm M}_{\odot}\, h^{-1} < {\rm M} < 10^{11}\, {\rm M}_{\odot}\, h^{-1}$ and redshifts $5{<}z{<}10$,…

The braneworld model of Dvali, Gabadadze and Porrati (DGP) provides an intriguing modification of gravity at large distances and late times. By embedding a three-brane in an uncompactified extra dimension with separate Einstein-Hilbert…

Astrophysics · Physics 2007-05-23 Ignacy Sawicki , Sean M. Carroll

The expansion of the Universe is accelerated as testified by observations of SNeIa at varying redshifts. Explanations of this acceleration are of two kinds: modifications of Einstein gravity or new forms of energy. An example of modified…

Astrophysics · Physics 2011-11-10 M. Roos

Constraints on the properties of the cosmological dark matter have previously been obtained in a model-independent fashion using the Generalised Dark Matter (GDM) framework. Here we extend that work in several directions: We consider the…

Cosmology and Nongalactic Astrophysics · Physics 2020-05-05 Daniel B Thomas , Michael Kopp , Katarina Markovič

We introduce and demonstrate the power of a method to speed up current iterative techniques for N-body modified gravity simulations. Our method is based on the observation that the accuracy of the final result is not compromised if the…

Cosmology and Nongalactic Astrophysics · Physics 2016-01-12 Alexandre Barreira , Sownak Bose , Baojiu Li