Ultra-fine dark matter structure in the Solar neighbourhood

Abstract

The direct detection of dark matter on Earth depends crucially on its density and its velocity distribution on a milliparsec scale. Conventional N-body simulations are unable to access this scale, making the development of other approaches necessary. In this paper, we apply the method developed in Fantin et al. 2008 to a cosmologically-based merger tree, transforming it into a useful instrument to reproduce and analyse the merger history of a Milky Way-like system. The aim of the model is to investigate the implications of any ultra-fine structure for the current and next generation of directional dark matter detectors. We find that the velocity distribution of a Milky Way-like Galaxy is almost smooth, due to the overlap of many streams of particles generated by multiple mergers. Only the merger of a 10^10 Msun analyse can generate significant features in the ultra-local velocity distribution, detectable at the resolution attainable by current experiments.

9 pages, 6 figures, accepted for publication in MNRAS

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• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• Cosmological Constraints from the SDSS Luminous Red Galaxies
• The RAVE Survey: Constraining the Local Galactic Escape Speed
• First Dark Matter Results from the XENON100 Experiment
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• The Excursion Set Theory of Halo Mass Functions, Halo Clustering, and Halo Growth
• Phase-space structure in the local dark matter distribution and its signature in direct detection experiments
• The fine-grained phase-space structure of Cold Dark Matter halos
• The Destruction of Thin Stellar Disks Via Cosmologically Common Satellite Accretion Events
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• Ultra-fine dark matter structure in the Solar neighbourhood

Cited by in corpus (7)

• The Local Dark Matter Density
• Astrophysical uncertainties on direct detection experiments
• The Distribution of Dark Matter in the Milky Way's Disk
• The local dark matter phase-space density and impact on WIMP direct detection
• Impact of Dark Matter Velocity Distributions on Capture Rates in the Sun
• Probing the Local Velocity Distribution of WIMP Dark Matter with Directional Detectors
• Ultra-fine dark matter structure in the Solar neighbourhood