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We present a perturbative treatment of nonlinear galaxy clustering in the context of the cubic Galileon modified gravity model, in terms of 2nd order Lagrangian Perturbation theory and an extension of ellipsoidal collapse that includes…

Cosmology and Nongalactic Astrophysics · Physics 2022-10-14 Yanling Song , Chiara Moretti , Pierluigi Monaco , Bin Hu

We present an upgraded version of \textsc{MG-MAMPOSSt}, an extension of the \textsc{MAMPOSSt} algorithm that performs Bayesian fits of models of mass and velocity anisotropy profiles to the distribution of tracers in projected phase space,…

Cosmology and Nongalactic Astrophysics · Physics 2021-07-13 Lorenzo Pizzuti , Ippocratis D. Saltas , Luca Amendola

Accurate cosmological simulations that include the effect of non-linear matter clustering as well as of massive neutrinos are essential for measuring the neutrino mass scale from upcoming galaxy surveys. Typically, Newtonian simulations are…

Cosmology and Nongalactic Astrophysics · Physics 2020-09-24 Christian Partmann , Christian Fidler , Cornelius Rampf , Oliver Hahn

We present an algorithm for quickly generating multiple realizations of N-body simulations to be used, for example, for cosmological parameter estimation from surveys of large-scale structure. Our algorithm uses a new method to resample the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Michael D. Schneider , Shaun Cole , Carlos S. Frenk , Istvan Szapudi

We perform N-body simulations of theories with infinite-volume extra dimensions, such as the Dvali-Gabadadze-Porrati (DGP) model and its higher-dimensional generalizations, where 4D gravity is mediated by massive gravitons. The longitudinal…

Cosmology and Nongalactic Astrophysics · Physics 2009-11-06 Justin Khoury , Mark Wyman

We propose a simple and computationally fast method for performing N-body simulations for a large class of modified gravity theories with a screening mechanism such as chameleons, symmetrons and galileons. By combining the linear…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-22 Hans A. Winther , Pedro G. Ferreira

Massive gravity, galileon and braneworld models that modify gravity to explain cosmic acceleration utilize the nonlinear field interactions of the Vainshtein mechanism to screen fifth forces in high density regimes. These source-dependent…

General Relativity and Quantum Cosmology · Physics 2013-04-24 Alexander V. Belikov , Wayne Hu

We test the convergence of fast simulations based on the COmoving Lagrangian Acceleration (COLA) method for predictions of the matter power spectrum, specialising our analysis in the redshift range $1 \le z \le 1.65$, relevant to…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-21 Bartolomeo Fiorini , Kazuya Koyama , Tessa Baker

Screening mechanisms are essential features of dark energy models mediating a fifth force on large scales. We study the regime of strong scalar field nonlinearities, known as Vainshtein screening, in the most general scalar-tensor theories…

General Relativity and Quantum Cosmology · Physics 2018-06-06 Alexandru Dima , Filippo Vernizzi

We present a novel method for including the impact of massive neutrinos in cold dark matter N-body simulations. Our approach is compatible with widely employed Newtonian N-body codes and relies on only three simple modifications. First, we…

Cosmology and Nongalactic Astrophysics · Physics 2022-10-05 Pol Heuschling , Christian Partmann , Christian Fidler

One of the main objectives of stage IV galaxy surveys is to constrain gravity on cosmological scales. To this end, it is crucial to make accurate theoretical predictions in the nonlinear regime of structure formation in order to maximise…

Cosmology and Nongalactic Astrophysics · Physics 2023-03-14 Bartolomeo Fiorini

The N-body dark matter (DM) simulations point that DM density profiles, e.g. the NFW halo, should be cuspy in its center, but observations disfavour this kind of DM profile. Here we consider whether the observed rotation curves "close" to…

Astrophysics of Galaxies · Physics 2014-11-04 Davi C. Rodrigues , Paulo L. de Oliveira , Julio C. Fabris , Gianfranco Gentile

In the last decades cosmological N-body dark matter simulations have enabled ab initio studies of the formation of structure in the Universe. Gravity amplified small density fluctuations generated shortly after the Big Bang, leading to the…

Instrumentation and Methods for Astrophysics · Physics 2016-11-18 Ralf Kaehler , Oliver Hahn , Tom Abel

It is well established that maximizing the information extracted from upcoming and ongoing stage-IV weak-lensing surveys requires higher-order summary statistics that complement the standard two-point statistics. In this work, we focus on…

Cosmology and Nongalactic Astrophysics · Physics 2024-08-02 Christopher T. Davies , Joachim Harnois-Déraps , Baojiu Li , Benjamin Giblin , César Hernández-Aguayo , Enrique Paillas

We forecast constraints on minimal model-independent parametrisations of several Modified Gravity theories using mock Stage-IV cosmic shear data. We include nonlinear effects and screening, which ensures recovery of General Relativity on…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-18 Maria Tsedrik , Benjamin Bose , Pedro Carrilho , Alkistis Pourtsidou , Sefa Pamuk , Santiago Casas , Julien Lesgourgues

The recent observational data in cosmology seem to indicate that the universe is currently expanding in an accelerated way. An intriguing interpretation of these data is that they may just be signalling that Einstein's General Relativity is…

High Energy Physics - Theory · Physics 2018-05-18 Fulvio Sbisà

In this work we systematically study the linear and nonlinear structure formation in chameleon theories of modified gravity, using a generic parameterisation which describes a large class of models using only 4 parameters. For this we have…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-24 Philippe Brax , Anne-C. Davis , Baojiu Li , Hans A. Winther , Gong-Bo Zhao

In this paper we present preliminary results from cosmological simulations of modified gravity in the dark matter sector. Our results show improvements over standard cold dark matter cosmology. The abundance of low-mass haloes in the…

Astrophysics · Physics 2008-07-08 Wojciech A. Hellwing

We present a novel, fast and precise method for including the effect of light neutrinos in cosmological N-body simulations. The effect of the neutrino component is included by using the linear theory neutrino perturbations in the…

Astrophysics · Physics 2010-04-15 Jacob Brandbyge , Steen Hannestad

In the context of scalar tensor theories for gravity, there is a universally adopted hypothesis when running N-body simulations that time derivatives in the equation of motion for the scalar field are negligible. In this work we propose to…

Cosmology and Nongalactic Astrophysics · Physics 2014-09-04 Claudio Llinares , David F. Mota