Physics of galactic colliders: high speed satellites in LCDM vs MONDian cosmology

Abstract

The statistics of high speed satellite galaxies, as reported in the recent literature, can be a powerful diagnosis of the depth of the potential well of the host halo, and hence discriminate between competing gravitational theories. Naively one expects that high speed satellites are more common in Modified Newtonian Dynamics (MOND) than in cold dark matter (CDM) since an isolated MONDian system has an infinite potential well, while CDM halos have finite potential wells. In this \textit{Letter} we report on an initial test of this hypothesis in the context of the first generation of cosmological simulations utilising a rigorous MONDian Poisson solver. We find that such high speed encounters are approximately a factor of four more common in MOND than in the concordance $\Lambda$CDM model of cosmic structure formation.

4 pages. 2 figures. Accepted for publication in ApJL

References in corpus (18)

• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• Revealing the properties of dark matter in the merging cluster MACSJ0025.4-1222
• The speed of the `bullet' in the merging galaxy cluster 1E0657-56
• Dark matter subhalos and the dwarf satellites of the Milky Way
• Discovery of a Ringlike Dark Matter Structure in the Core of the Galaxy Cluster Cl 0024+17
• The dark matter environment of the Abell 901/902 supercluster: a weak lensing analysis of the HST STAGES survey
• Milky Way potentials in CDM and MOND. Is the Large Magellanic Cloud on a bound orbit?
• Escaping from MOND
• Cosmological Structure Formation under MOND: a new numerical solver for Poisson's equation
• How Rare is the Bullet Cluster?
• Coincidences of Dark Energy with Dark Matter -- Clues for a Simple Alternative?
• Loss of mass and stability of galaxies in MOND
• The Dynamics of Subhalos in Warm Dark Matter Models
• The collision velocity of the bullet cluster in conventional and modified dynamics
• Forming Galaxies with MOND
• Asymmetric Gravitational Lenses in TeVeS and Application to the Bullet Cluster
• Back-in-time dynamics of the cluster IE 0657-56 (the Bullet System)
• Galaxy Bulges As Tests of CDM vs MOND in Strong Gravity

Cited by in corpus (3)

• A simple multigrid scheme for solving the Poisson equation with arbitrary domain boundaries
• Halo velocity profiles in screened modified gravity theories
• Modified Kepler's Law, Escape Speed and Two-body Problem in MOND-like Theories