Empirical Determination of Dark Matter Velocities Using Metal-Poor Stars

Area of Science:

• Astrophysics
• Cosmology
• Galactic Astronomy

Background:

• The Milky Way's dark matter halo grows through the merger of smaller structures (subhalos).
• These subhalos contain old, metal-poor stars that are deposited into the inner galaxy.
• These stars and dark matter may share common origins and kinematics.

Purpose of the Study:

• To investigate if metal-poor stars can trace the local dark matter velocity distribution.
• To compare the empirical dark matter distribution with the standard halo model.
• To assess the implications for dark matter detection experiments.

Main Methods:

• Utilized the high-resolution eris simulation of a Milky Way analog galaxy.
• Analyzed the kinematics of dark matter and metal-poor stars within the simulation.
• Compared simulated stellar halo data with observations from the Sloan Digital Sky Survey.

Main Results:

• Demonstrated that metal-poor stars effectively trace the local dark matter velocity distribution.
• Showed that the empirical dark matter velocity distribution differs from the standard halo model.
• Identified potential implications for spin-independent scattering cross-section limits for dark matter below 10 GeV.

Conclusions:

• Metal-poor stars serve as valuable tracers for local dark matter.
• The study refines our understanding of dark matter distribution in the Solar neighborhood.
• Future data from Gaia will further improve dark matter distribution models and substructure detection.