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We study spherical collapse in the Quartic and Quintic Covariant Galileon gravity models within the framework of the excursion set formalism. We derive the nonlinear spherically symmetric equations in the quasi-static and weak-field limits,…

Cosmology and Nongalactic Astrophysics · Physics 2014-04-24 Alexandre Barreira , Baojiu Li , Carlton Baugh , Silvia Pascoli

We present a detailed study of the collapse of a spherical matter overdensity and the non-linear growth of large scale structures in the Galileon ghost condensate (GGC) model. This model is an extension of the cubic covariant Galileon (G3)…

Cosmology and Nongalactic Astrophysics · Physics 2020-07-22 Noemi Frusciante , Francesco Pace

We compute the critical density of collapse for spherically symmetric overdensities in a class of f(R) modified gravity models. For the first time we evolve the Einstein, scalar field and non-linear fluid equations, making the minimal…

Cosmology and Nongalactic Astrophysics · Physics 2013-11-26 Michael Kopp , Stephen A. Appleby , Ixandra Achitouv , Jochen Weller

We study the gravitational clustering of spherically symmetric overdensities and the statistics of the resulting dark matter halos in the "symmetron model", in which a new long range force is mediated by a $Z_2$ symmetric scalar field.…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Laura Taddei , Riccardo Catena , Massimo Pietroni

In this paper we study the evolution of a spherical matter overdensity in the context of the recently introduced Galileon field theory. Our analysis considers the complete covariant Lagrangian in four dimensions. This theory is composed by…

Cosmology and Nongalactic Astrophysics · Physics 2013-11-20 Emilio Bellini , Nicola Bartolo , Sabino Matarrese

We analyse modelling techniques for the large-scale structure formed in scalar-tensor theories of constant Brans-Dicke parameter which match the concordance model background expansion history and produce a chameleon suppression of the…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-14 Lucas Lombriser , Kazuya Koyama , Baojiu Li

I examine differences in non-linear structure formation between cosmological models that share a $z=0$ linear power spectrum in both shape and amplitude, but that differ via their growth history. $N$-body simulations of these models display…

Cosmology and Nongalactic Astrophysics · Physics 2018-03-15 Alexander Mead

We study the spherical collapse model (SCM) in the framework of spatially flat power law $f(T) \propto (-T)^{b}$ gravity model. We find that the linear and non-linear growth of spherical overdensities of this particular $f(T)$ model are…

General Relativity and Quantum Cosmology · Physics 2017-02-17 Mohammad Malekjani , Spyros Basilakos , Neda Heidari

We combine the physics of the ellipsoidal collapse model with the excursion set theory to study the shapes of dark matter halos. In particular, we develop an analytic approximation to the nonlinear evolution that is more accurate than the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Graziano Rossi , Ravi K. Sheth , Giuseppe Tormen

We study the nonlinear growth of structure in nonlocal gravity models with the aid of N-body simulation and the spherical collapse and halo models. We focus on a model in which the inverse-squared of the d'Alembertian operator acts on the…

Cosmology and Nongalactic Astrophysics · Physics 2014-09-25 Alexandre Barreira , Baojiu Li , Wojciech A. Hellwing , Carlton M. Baugh , Silvia Pascoli

We study the gravitational collapse of an overdensity of nonrelativistic matter under the action of gravity and a chameleon scalar field. We show that the spherical collapse model is modified by the presence of a chameleon field. In…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-17 Ph. Brax , R. Rosenfeld , D. A. Steer

We study cosmological consequences of a kinetic gravity braiding model, which is proposed as an alternative to the dark energy model. The kinetic braiding model we study is characterized by a parameter n, which corresponds to the original…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-17 Rampei Kimura , Kazuhiro Yamamoto

We study structure formation in K-mouflage cosmology whose main feature is the absence of screening effect on quasilinear scales. We show that the growth of structure at the linear level is affected by both a new time dependent Newton…

Cosmology and Nongalactic Astrophysics · Physics 2014-12-02 Philippe Brax , Patrick Valageas

I review the main steps made so far towards the construction of a (semi) analytical model for describing the growth history of bound virialized objects or haloes in the gravitational instability scenario. I mainly focus on those models…

Astrophysics · Physics 2007-05-23 E. Salvador-Sole

The abundance of massive dark matter halos hosting galaxy clusters provides an important test of the masses of relic neutrino species. The dominant effect of neutrino mass is to lower the typical amplitude of density perturbations that…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-03 Marilena LoVerde

We present constraints on the flat $\Lambda$CDM cosmological model through a joint analysis of galaxy abundance, galaxy clustering and galaxy-galaxy lensing observables with the Kilo-Degree Survey. Our theoretical model combines a flexible…

We refine the mass and environment dependent spherical collapse model of chameleon $f(R)$ gravity by calibrating a phenomenological correction inspired by the parameterized post-Friedmann framework against high-resolution $N$-body…

Cosmology and Nongalactic Astrophysics · Physics 2017-04-12 Matteo Cataneo , David Rapetti , Lucas Lombriser , Baojiu Li

We investigate the performance of semi-analytical modelling of large-scale structure in Galileon gravity cosmologies using results from N-body simulations. We focus on the Cubic and Quartic Galileon models that provide a reasonable fit to…

Cosmology and Nongalactic Astrophysics · Physics 2014-05-05 Alexandre Barreira , Baojiu Li , Wojciech A. Hellwing , Lucas Lombriser , Carlton M. Baugh , Silvia Pascoli

We generalize the spherical collapse model for the formation of bound objects to apply in a Universe with arbitrary positive cosmological constant. We calculate the critical condition for collapse of an overdense region and give exact…

Astrophysics · Physics 2007-05-23 Ewa L. Lokas , Yehuda Hoffman

We study the evolution of the halo-halo correlation function and bias in four cosmological models (LCDM, OCDM, tauCDM, and SCDM) using very high-resolution N-body simulations. The high force and mass resolution allows dark matter (DM) halos…

Astrophysics · Physics 2009-10-30 Pedro Colin , Anatoly Klypin , Andrey Kravtsov , Alexei Khokhlov
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