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We consider $f(R)$ modified gravity theory incorporating the chameleon mechanism to address galactic dynamics. By employing the metric formalism and utilizing a conformal transformation, we simplify the field equations and describe the…

General Relativity and Quantum Cosmology · Physics 2024-09-04 Gayatri Mohan , Umananda Dev Goswami

We calculate the geometric phase for different open systems (spin-boson and spin-spin models). We study not only how they are corrected by the presence of the different type of environments but also discuss the appearence of decoherence…

Quantum Physics · Physics 2008-03-11 Fernando C. Lombardo , Paula I. Villar

Current acceleration of the cosmic expansion leads to coincidence as well as fine-tuning issues in the framework of general relativity. Dynamical scalar fields have been introduced in response of these problems, some of them invoking…

Cosmology and Nongalactic Astrophysics · Physics 2015-12-25 Sandrine Schlogel , Sebastien Clesse , Andre Fuzfa

We use a high-resolution N-body simulation to study how the influence of large-scale structure in and around clusters causes correlated signals in different physical probes and discuss some implications this has for multi-physics probes of…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Martin White , J. D. Cohn , Renske Smit

The GammeV experiment has constrained the couplings of chameleon scalar fields to matter and photons. Here we present a detailed calculation of the chameleon afterglow rate underlying these constraints. The dependence of GammeV constraints…

High Energy Physics - Phenomenology · Physics 2010-02-24 A. Upadhye , J. H. Steffen , A. Weltman

A modified gravity (MOG) theory, that has been successfully fitted to galaxy rotational velocity data, cluster data, the Bullet Cluster 1E0657-56 and cosmological observations, is shown to be in good agreement with the motion of satellite…

Astrophysics · Physics 2008-08-10 J. W. Moffat , V. T. Toth

The mass of a scalar field mediating a fifth force is tightly constrained by experiments. We show, however, that adding a quartic self-interaction for such a scalar makes most tests much less constraining: the non-linear equation of motion…

High Energy Physics - Phenomenology · Physics 2009-11-10 Steven S. Gubser , Justin Khoury

We use group size haloes identified with a ``friends of friends'' (FOF) algorithm in a concordance $\Lambda \rm{CDM}$ GADGET2 (dark matter only) simulation to investigate the dependence of halo properties on the environment at $z=0$. The…

Astrophysics · Physics 2008-11-26 Cinthia Ragone-Figueroa , Manolis Plionis

We search for detectable signatures of f(R) gravity and its chameleon screening mechanism in the baryonic and dark matter (DM) properties of simulated void galaxies. The enhancement of the gravitational acceleration can have a meaningful…

Astrophysics of Galaxies · Physics 2022-08-17 Pedro Cataldi , Susana Pedrosa , Nelson Padilla , Susana Landau , Christian Arnold , Baojiu Li

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

New covariant theories of emergent modified gravity exist not only in spherically symmetric models, as previously found, but also in polarized Gowdy systems that have a local propagating degree of freedom. Several explicit versions are…

General Relativity and Quantum Cosmology · Physics 2024-12-04 Martin Bojowald , Erick I. Duque

We investigate the effects of a K-mouflage modification of gravity on the dynamics of clusters of galaxies. We extend the description of K-mouflage to situations where the scalar field responsible for the modification of gravity is coupled…

Cosmology and Nongalactic Astrophysics · Physics 2016-06-13 Philippe Brax , Luca Alberto Rizzo , Patrick Valageas

We analyse the conservative evolution of spinning compact binaries to second post-Newtonian (2PN) order accuracy, with leading order spin-orbit, spin-spin and mass quadrupole-monopole contributions included. As a main result we derive a…

General Relativity and Quantum Cosmology · Physics 2015-05-04 László Árpád Gergely , Zoltán Keresztes

We show that Solar System tests can place very strong constraints on K-mouflage models of gravity, which are coupled scalar field models with nontrivial kinetic terms that screen the fifth force in regions of large gravitational…

Cosmology and Nongalactic Astrophysics · Physics 2015-07-28 Alexandre Barreira , Philippe Brax , Sebastien Clesse , Baojiu Li , Patrick Valageas

We study potential systematic effects of assembly bias on cosmological parameter constraints from redshift space distortion measurements. We use a semi-analytic galaxy formation model applied to the Millennium N-body WMAP-7 simulation to…

Cosmology and Nongalactic Astrophysics · Physics 2019-03-27 Nelson Padilla , Sergio Contreras , Idit Zehavi , Carlton Baugh , Peder Norberg

We study the effect of baryonic processes on the halo mass function in the galaxy cluster mass range using a catalogue of 153 high resolution cosmological hydrodynamical simulations performed with the AMR code ramses. We use the results of…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Davide Martizzi , Irshad Mohammed , Romain Teyssier , Ben Moore

We use a large dark matter simulation of a LambdaCDM model to investigate the clustering and environmental dependence of the number of substructures in a halo. Focusing on redshift z=1, we find that the halo occupation distribution is…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Rupert Croft , Tiziana Di Matteo , Nishikanta Khandai , Volker Springel , Anirban Jana , Jeffrey Gardner

We perform a phase space analysis of a generalized modified gravity theory with nonminimally coupling between geometry and matter. We apply the dynamical system approach to this generalized model and find that in the cosmological context,…

General Relativity and Quantum Cosmology · Physics 2016-05-17 Rui An , Xiaodong Xu , Bin Wang , Yungui Gong

We investigate potential systematic effects in constraining the amplitude of primordial fluctuations \sigma_8 arising from the choice of halo mass function in the likelihood analysis of current and upcoming galaxy cluster surveys. We study…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-23 Aseem Paranjape

We study the thermodynamics of galactic clustering under the higher-order corrected Newtonian dynamics. The clustering of galaxies is considered as a gravitational phase transition. In order to study the effects of higher-order correction…

General Relativity and Quantum Cosmology · Physics 2019-01-23 Sudhaker Upadhyay , Behnam Pourhassan , Salvatore Capozziello