Dynamics of the Local Group: the Dwarf Galaxies

Abstract

I present a dynamical analysis of the measured redshifts and distances of 64 dwarf galaxies at distances between 50 kpc and 2.6 Mpc. These dwarfs are assumed to move as test particles in the gravitational field of 12 massive actors---galaxies and groups of galaxies---under the mixed boundary conditions imposed by cosmology. The model fits most of the measured dwarf distances and redshifts. But more work, perhaps on the gravitational interaction among dwarf galaxies, is required to account for the motions of six galaxies in the NGC 3109 association and two in the DDO 210 association. The sample of dwarfs is large enough to constrain the halo mass run in the Milky Way. The evidence points to a sharper break from a nearly flat inner rotation curve than predicted by the NFW profile.

References in corpus (5)

• Orbits of massive satellite galaxies: II. Bayesian Estimates of the Milky Way and Andromeda masses using high precision astrometry and cosmological simulations
• A Dynamical Model of the Local Group
• The Variety of Solutions for Dynamics in the Local Group
• Orbit of the Large Magellanic Cloud in a Dynamical Model for the Local Group
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• The proper motion of Andromeda from Gaia eDR3: confirming a nearly radial orbit
• The ultra-diffuse dwarf galaxies NGC 1052-DF2 and 1052-DF4 are in conflict with standard cosmology
• Directly testing gravity with Proxima Centauri
• Equilibrium axisymmetric halo model for the Milky Way and its implications for direct and indirect DM searches
• Detection of the Intrinsic Spin Alignments in Isolated Spiral Pairs
• Improving Physical Cosmology: An Empiricist's Assessment
• Distinguishing Standard from Modified Gravity in the Local Group and beyond
• Dynamics of the Local Group: the Outer Galactic Globular Star Clusters