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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 use N-body simulations to study the statistics of massive halos and redshift space distortions for theories with a standard \Lambda CDM expansion history and a galileon-type scalar field. The extra scalar field increases the…

Cosmology and Nongalactic Astrophysics · Physics 2013-10-30 Mark Wyman , Elise Jennings , Marcos Lima

The DBI-Galileon model is a scalar-tensor theory of gravity which is defined as the most general theory of the dynamics of a 4D brane embedded in a 5D bulk. It is of particular interest as it introduces only a few free parameters, all with…

High Energy Physics - Theory · Physics 2023-12-15 C. Leloup , L. Heitz , J. Neveu

The comparison between dynamical mass and lensing mass provides a targeted test for a wide range of modified gravity models. In our previous paper we showed, through numerical simulations, that the measurement of the line-of-sight velocity…

Cosmology and Nongalactic Astrophysics · Physics 2013-08-05 Tsz Yan Lam , Fabian Schmidt , Takahiro Nishimichi , Masahiro Takada

We develop a parameterized post-Friedmann (PPF) framework which describes three regimes of modified gravity models that accelerate the expansion without dark energy. On large scales, the evolution of scalar metric and density perturbations…

Astrophysics · Physics 2008-11-26 Wayne Hu , Ignacy Sawicki

In this series of papers we present an emulator-based halo model for the non-linear clustering of galaxies in modified gravity cosmologies. In the first paper, we present emulators for the following halo properties: the halo mass function,…

Theories of modified gravity, in both the linear and fully non-linear regime, are often studied under the assumption that the evolution of the new (often scalar) degree of freedom present in the theory is quasi-static. This approximation…

General Relativity and Quantum Cosmology · Physics 2015-09-09 Hans A. Winther , Pedro G. Ferreira

After defining conformal Galilean-type algebras for arbitrary dynamical exponent $z$ we consider the particular cases of the conformal Galilei algebra (CGA) and the Schr\"odinger Lie algebra (sch). Galilei massless particles moving with…

High Energy Physics - Theory · Physics 2009-08-11 Peter C. Stichel

Two alternative theories to dark matter are investigated by testing their ability to describe consistently the dynamics of the Milky Way. The first one refers to a modified gravity theory having a running gravitational constant and the…

Astrophysics of Galaxies · Physics 2015-01-20 P. L. C. de Oliveira , J. A. de Freitas Pacheco , G. Reinisch

Halo phenomena in deformed nuclei are investigated within a deformed relativistic Hartree Bogoliubov (DRHB) theory. These weakly bound quantum systems present interesting examples for the study of the interdependence between the deformation…

Nuclear Theory · Physics 2014-11-20 Shan-Gui Zhou , Jie Meng , P. Ring , En-Guang Zhao

In the present work, we adopt a nonlinear scalar field theory coupled to the gravity sector to model galactic dark matter. We found analytical solutions for the scalar field coupled to gravity in the Newtonian limit, assuming an isotropic…

General Relativity and Quantum Cosmology · Physics 2021-05-19 R. A. C. Correa , P. H. R. S. Moraes , A. de Souza Dutra , O. L. Dors , W. de Paula , T. Frederico

We present a new method to construct fully self-consistent equilibrium models of multi-component disc galaxies similar to the Milky Way. We define distribution functions for the stellar disc and dark halo that depend on phase space position…

Astrophysics of Galaxies · Physics 2015-07-03 T. Piffl , Z. Penoyre , J. Binney

We study the growth of structures in modified gravity models where the Poisson equation and the relationship between the two Newtonian potentials are modified by explicit functions of space and time. This parameterisation applies to the…

Cosmology and Nongalactic Astrophysics · Physics 2012-10-24 Philippe Brax , Patrick Valageas

We present a novel fitting formula for the halo concentration enhancement in chameleon $f(R)$ gravity relative to General Relativity (GR). The formula is derived by employing a large set of $N$-body simulations of the Hu-Sawicki $f(R)$…

Cosmology and Nongalactic Astrophysics · Physics 2019-06-04 Myles A. Mitchell , Christian Arnold , Jian-hua He , Baojiu Li

In the pursuit of a general formulation for a modified gravitational theory at the non-relativistic level and as an alternative to the dark matter hypothesis, we construct a model valid over a wide variety of astrophysical scales. Through…

Astrophysics of Galaxies · Physics 2011-12-13 S. Mendoza , X. Hernandez , J. C. Hidalgo , T. Bernal

We revisit the construction of models of quantum gravity in d dimensional Minkowski space in terms of random tensor models, and correct some mistakes in our previous treatment of the subject. We find a large class of models in which the…

High Energy Physics - Theory · Physics 2020-03-10 Tom Banks , Willy Fischler

We present a non-linear analysis of perturbations around cosmological solutions in Generalised Massive gravity. This Lorentz invariant theory is an extension of de Rham, Gabadadze, Tolley massive gravity that propagates $5$ degrees of…

High Energy Physics - Theory · Physics 2021-09-22 A. Emir Gumrukcuoglu , Rampei Kimura , Michael Kenna-Allison , Kazuya Koyama

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…

We study the halo mass function (HMF) in modified gravity (MG) models using a set of large $N$-body simulations -- the ELEPHANT suite. We consider two popular beyond-general relativity scenarios: the Hu-Sawicki chameleon $f(R)$ model and…

Cosmology and Nongalactic Astrophysics · Physics 2022-03-22 Suhani Gupta , Wojciech A. Hellwing , Maciej Bilicki , Jorge Enrique García-Farieta

Studying the physics of compact objects in modified theories of gravity is important for understanding how future observations can test alternatives to General Relativity. We consider a subset of vector-tensor Galileon theories of gravity…

High Energy Physics - Theory · Physics 2018-02-14 Javier Chagoya , Gianmassimo Tasinato