Halo velocity profiles in screened modified gravity theories

Abstract

Screened modified gravity predicts potentially large signatures in the peculiar velocity field that makes it an interesting probe to test gravity on cosmological scales. We investigate the signatures induced by the Symmetron and a Chameleon $f(R)$ model in the peculiar velocity field using $N$-body simulations. By studying fifth force and halo velocity profiles we identify three general categories of effects found in screened modified gravity models: a fully screened regime where we recover $\Lambda$CDM to high precision, an unscreened regime where the fifth force is in full operation, and, a partially screened regime where screening occurs in the inner part of a halo, but the fifth force is active at larger radii. These three regimes can be pointed out very clearly by analyzing the deviation in the maximum cluster velocity. Observationally, the partially screened regime is of particular interest since an uniform increase of the gravitational force - as present in the unscreened regime - is degenerate with the (dynamical) halo mass estimate, and, thus, hard to detect.

9 pages, 7 figures

References in corpus (11)

• Models of f(R) Cosmic Acceleration that Evade Solar-System Tests
• Beyond the Cosmological Standard Model
• Galileon Cosmology
• Strongly Coupled Chameleon Fields: New Horizons in Scalar Field Theory
• Screening Modifications of Gravity through Disformally Coupled Fields
• Dynamical Masses in Modified Gravity
• Theories of Dark Energy with Screening Mechanisms
• Testing the quasi-static approximation in $f(R)$ gravity simulations
• Domain walls coupled to matter: the symmetron example
• Variation of fundamental constants in space and time: theory and observations
• Physics of galactic colliders: high speed satellites in LCDM vs MONDian cosmology

Cited by in corpus (4)

• Gravitational transitions via the explicitly broken symmetron screening mechanism
• Estimates of cluster masses in screened modified gravity
• Dynamics of pairwise motions in the fully non-linear regime in LCDM and Modified Gravity cosmologies
• CLASH-VLT: The Fifth Force in Chameleon Gravity from Joint Lensing and Kinematics Cluster Mass Profiles