Empirical Determination of Dark Matter Velocities Using Metal-Poor Stars
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PhysRevLett.120.041102.pdf
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311.68 KB
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Author(s)
Herzog-Arbeitman, Jonah
Lisanti, Mariangela
Madau, Piero
Necib, Lina
Date Issued
January 2018
Journal
Physical Review Letters
Publisher
American Physical Society
Citation
Herzog-Arbeitman, Jonah et al. "Empirical Determination of Dark Matter Velocities Using Metal-Poor Stars." Physical Review Letters 120, 4 (January 2018): 041102 © 2018 American Physical Society
Version
Final published version
Abstract
The Milky Way dark matter halo is formed from the accretion of smaller subhalos. These sub-units also harbor stars—typically old and metal-poor—that are deposited in the Galactic inner regions by disruption events. In this Letter, we show that the dark matter and metal-poor stars in the Solar neighborhood share similar kinematics due to their common origin. Using the high-resolution eris simulation, which traces the evolution of both the dark matter and baryons in a realistic Milky Way analog galaxy, we demonstrate that metal-poor stars are indeed effective tracers for the local, virialized dark matter velocity distribution. The local dark matter velocities can therefore be inferred from observations of the stellar halo made by the Sloan Digital Sky Survey within 4 kpc of the Sun. This empirical distribution differs from the standard halo model in important ways and suggests that the bounds on the spin-independent scattering cross section may be weakened for dark matter masses below ∼10 GeV. Data from Gaia will allow us to further refine the expected distribution for the smooth dark matter component, and to test for the presence of local substructure.
MIT Department
Massachusetts Institute of Technology. Center for Theoretical Physics
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DOI of Published Version
https://doi.org/10.1103/PhysRevLett.120.041102
