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We assess the effectiveness of a non-parametric bias model in generating mock halo catalogues for modified gravity (MG) cosmologies, relying on the distribution of dark matter from either MG or $\Lambda$CDM. We aim to generate halo…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-02 Jorge Enrique García-Farieta , Andrés Balaguera-Antolínez , Francisco-Shu Kitaura

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 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

In this paper, we describe the implementation and performance of GreeM, a massively parallel TreePM code for large-scale cosmological N-body simulations. GreeM uses a recursive multi-section algorithm for domain decomposition. The size of…

Instrumentation and Methods for Astrophysics · Physics 2015-05-14 Tomoaki Ishiyama , Toshiyuki Fukushige , Junichiro Makino

We present a new C++ code for collisional N-body simulations of star clusters. The code uses the Hermite fourth-order scheme with block time steps, for advancing the particles in time, while the forces and neighboring particles are computed…

Instrumentation and Methods for Astrophysics · Physics 2010-11-08 Simos Konstantinidis , Kostas D. Kokkotas

We perform high resolution N-body simulations for f(R) gravity based on a self-adaptive particle- mesh code MLAPM. The Chameleon mechanism that recovers General Relativity on small scales is fully taken into account by self-consistently…

Cosmology and Nongalactic Astrophysics · Physics 2011-02-18 Gong-Bo Zhao , Baojiu Li , Kazuya Koyama

Model-independent constraints on modified gravity models hitherto exist mainly on linear scales. A recently developed formalism presented a consistent parameterisation that is valid on all scales. Using this approach, we perform…

Cosmology and Nongalactic Astrophysics · Physics 2021-06-15 Sankarshana Srinivasan , Daniel B Thomas , Francesco Pace , Richard Battye

Accurate predictions for the non-linear matter power spectrum are needed to confront theory with observations in current and near future weak lensing and galaxy clustering surveys. We propose a computationally cheap method to create an…

Cosmology and Nongalactic Astrophysics · Physics 2020-01-01 Hans Winther , Santiago Casas , Marco Baldi , Kazuya Koyama , Baojiu Li , Lucas Lombriser , Gong-Bo Zhao

Testing gravity and the concordance model of cosmology, $\Lambda$CDM, at large scales is a key goal of this decade's largest galaxy surveys. Here we present a comparative study of dark matter power spectrum predictions from different…

In the last two decades, Modified Gravity (MG) models have been proposed to explain the accelerated expansion of the Universe. However, one of the main difficulties these theories face is that they must reduce to General Relativity (GR) at…

General Relativity and Quantum Cosmology · Physics 2021-10-27 Alejandro Aviles

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

This is the first in a series of papers devoted to fully general-relativistic $N$-body simulations applied to late-time cosmology. The purpose of this paper is to present the combination of a numerical relativity scheme, discretization…

Cosmology and Nongalactic Astrophysics · Physics 2019-10-29 David Daverio , Yves Dirian , Ermis Mitsou

As one of the most powerful probes of cosmological structure formation, the abundance of massive galaxy clusters is a sensitive probe of modifications to gravity on cosmological scales. In this paper, we present results from N-body…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-17 Simone Ferraro , Fabian Schmidt , Wayne Hu

We apply a halo velocity bias model, $\gamma_{f}$, within the Aemulus simulation suite for General Relativity (GR) to investigate its efficacy in identifying the signature of assembly bias and Modified Gravity (MG). In the investigation of…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-01 Yirong Wang , Zhongxu Zhai , Xiaohu Yang , Jeremy L. Tinker

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

We present a new N-body and gas dynamics code, called Nyx, for large-scale cosmological simulations. Nyx follows the temporal evolution of a system of discrete dark matter particles gravitationally coupled to an inviscid ideal fluid in an…

Instrumentation and Methods for Astrophysics · Physics 2015-06-12 Ann Almgren , John Bell , Mike Lijewski , Zarija Lukić , Ethan Van Andel

We address the generation of initial conditions (ICs) for GRAMSES, a code for nonlinear general relativistic (GR) $N$-body cosmological simulations recently introduced in Ref. [1]. GRAMSES adopts a constant mean curvature slicing with a…

Cosmology and Nongalactic Astrophysics · Physics 2020-05-06 Cristian Barrera-Hinojosa , Baojiu Li

We describe the newly written code GADGET which is suitable both for cosmological simulations of structure formation and for the simulation of interacting galaxies. GADGET evolves self-gravitating collisionless fluids with the traditional…

Astrophysics · Physics 2009-09-25 Volker Springel , Naoki Yoshida , Simon D. M. White

The parallel code NMAGIC is an implementation of a particle-based method to create made-to-measure models in agreement with observations of galaxies. It works by slowly correcting the particle weights of an evolving N-body system, until a…

Cosmology and Nongalactic Astrophysics · Physics 2012-07-30 Lucia Morganti , Ortwin Gerhard

Numerical methods have become a powerful tool for research in astrophysics, but their utility depends critically on the availability of suitable simulation codes. This calls for continuous efforts in code development, which is necessitated…

Instrumentation and Methods for Astrophysics · Physics 2021-08-19 Volker Springel , Rüdiger Pakmor , Oliver Zier , Martin Reinecke