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Related papers: Spherical Collapse in f(R) Gravity

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Using the liminality N-body simulations of Shi et. al., we present the first predictions for galaxy clustering in $f(R)$ gravity using subhalo abundance matching. We find that, for a given galaxy density, even for an $f(R)$ model with…

Cosmology and Nongalactic Astrophysics · Physics 2016-11-30 Jian-Hua He , Baojiu Li , Carlton M. Baugh

This manuscript is the first in a series of instalments that investigate spherically symmetric solutions within the effective dynamics program of Loop Quantum Gravity. The choice of lattice is adapted such that it remains invariant under a…

General Relativity and Quantum Cosmology · Physics 2026-02-27 Klaus Liegener , Saeed Rastgoo , Jorden Roberts

We have investigated structure formation in the $\gamma$ gravity $f(R)$ model with {\it N}-body simulations. The $\gamma$ gravity model is a proposal which, unlike other viable $f(R)$ models, not only changes the gravitational dynamics, but…

Cosmology and Nongalactic Astrophysics · Physics 2016-03-09 Marcelo Vargas dos Santos , Hans A. Winther , David F. Mota , Ioav Waga

We investigate nonlinear structure formation in Horndeski gravity with a luminal gravitational wave speed ($c_T = 1$) using the spherical collapse model incorporating Vainshtein screening. We compute the critical and virial overdensities…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-06 Dani de Boe , Mattia Pantiri , Gen Ye , Alessandra Silvestri

We perform numerical simulations of the critical gravitational collapse of a spherically symmetric scalar field in 6 dimensions. The critical solution has discrete self-similarity. We find the critical exponent \gamma and the…

General Relativity and Quantum Cosmology · Physics 2010-11-19 David Garfinkle , Curt Cutler , G. Comer Duncan

We study the gravitational collapse of a homogeneous scalar field, minimally coupled to gravity, in the presence of a particular type of dynamical deformation between the canonical momenta of the scale factor and of the scalar field. In the…

General Relativity and Quantum Cosmology · Physics 2014-03-05 S. M. M. Rasouli , A. H. Ziaie , J. Marto , P. V. Moniz

In the present work the collapse scenario of some exact non-spherical models with a minimally coupled scalar field is studied. Scalar field collapse with planar as well as toroidal, cylindrical and pseudoplanar symmetries have been…

General Relativity and Quantum Cosmology · Physics 2011-07-21 Koyel Ganguly , Narayan Banerjee

The collapsing dynamics of relativistic fluid are explored in $f(R)$ gravity in a detailed systematic manner for the non-static spherically symmetric spacetime satisfying the equation of the conformal Killing vector. With quasi-homologous…

General Relativity and Quantum Cosmology · Physics 2024-10-03 Kazuharu Bamba , Z. Yousaf , M. Z. Bhatti , R. Nazer , Yuki Hashimoto

Complete tensor-scalar and hydrodynamic equations are presented and integrated, for a self-gravitating perfect fluid. The initial conditions describe unstable-equilibrium neutron star configuration, with a polytropic equation of state. They…

General Relativity and Quantum Cosmology · Physics 2009-10-30 J. Novak

Future weak lensing surveys will directly probe the density fluctuation in the universe. Recent studies have shown how the statistics of the weak lensing convergence field is related to the statistics of collapsed objects. Extending earlier…

Astrophysics · Physics 2008-11-26 Dipak Munshi

We consider a general non-linear sigma model coupled to Einstein gravity and show that in spherical symmetry and for a simple realization of self-similarity, the spacetime can be completely determined. We also examine some more specific…

General Relativity and Quantum Cosmology · Physics 2009-07-07 Eric W. Hirschmann , Anzhong Wang

In this paper, we study the distribution of dark matter halos and voids using high resolution simulations in f(R) gravity models with the chameleon mechanism to screen the fifth force in dense environment. For dark matter halos, we show…

Cosmology and Nongalactic Astrophysics · Physics 2012-07-04 Baojiu Li , Gong-Bo Zhao , Kazuya Koyama

We review various approaches to approximating general relativistic effects in hydrodynamic simulations of stellar core collapse and post-bounce evolution. Different formulations of a modified Newtonian gravitational potential are presented.…

Astrophysics · Physics 2009-11-11 Harald Dimmelmeier , Pablo Cerda-Duran , Andreas Marek , Guillaume Faye

We study the collapse of the universe described by a scalar field spherically symmetric collapse of a system described by a massless scalar field from a 5D Riemann-flat canonical metric, on which we make a dynamical foliation on the extra…

General Relativity and Quantum Cosmology · Physics 2015-05-28 Mauricio Bellini

The physically realistic model of compact stars undergoing gravitational collapse in $ f(R) $ gravity has been developed. We consider a more general model $ R + f(R) = R + k R^m $ and describe the interior space-time of gravitationally…

General Relativity and Quantum Cosmology · Physics 2022-05-17 Jay Solanki

$f(R)$ theories of modified gravity may be compatible with current observations if the deviations from general relativity are sufficiently well screened in dense environments. In recent work [arXiv:2310.19955] we have shown that…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-20 Bradley March , Clare Burrage , Aneesh P. Naik

The accelerated expansion of the universe is a rather established fact in cosmology and many different models have been proposed as a viable explanation. Many of these models are based on the standard general relativistic framework of…

General Relativity and Quantum Cosmology · Physics 2016-05-20 N. Nazari-Pooya , M. Malekjani , F. Pace , D. Mohammad-Zadeh Jassur

We explore the real solutions to the Spherical Collapse Model in a non-flat Universe with a Cosmological Constant, and observe a possible situation for a fake or Ghost Collapse, in which an expanding overdense spherical region, turns around…

Cosmology and Nongalactic Astrophysics · Physics 2019-02-26 Aditya Vidhate , Rahul Nigam

Numerical investigation of the static spherically symmetric vacuum solution of the Logunov equations confirms the analytical results and demonstrates a strong repulsion at sub-Planckian distance from the Schwarzschild-like singularity,…

Astrophysics · Physics 2007-05-23 Vladimir L. Kalashnikov

Within the framework of hierarchical clustering scenarios, we investigate the consequences for the properties of virialized halos of the constraints provided by numerical simulations on the first few correlation functions. Thus, we show…

Astrophysics · Physics 2007-05-23 P. Valageas