Properties of Galactic Dark Matter: Constraints from Astronomical Observations

Abstract

The distributions of normal matter and of dark matter in the Galaxy are coupled to each other as they both move in the common gravitational potential. In order to fully exploit this interplay and to derive the various properties of dark matter relevant to their direct and indirect detection, we have comprehensively reviewed the astronomical observations of the spatial and velocity distributions of the components of normal matter. We then postulate that the phase-space distribution of dark matter follows a lowered-isothermal form and self-consistently solve Poisson's equation to construct several models for the spatial and velocity distributions of dark matter. In this paper, we compute the total gravitational potential of the normal and dark matter components and investigate their consistency with current observations of the rotation curve of the Galaxy and of the spatial and velocity distributions of blue horizontal-branch and blue straggler stars. Even with this demand of consistency, a large number of models with a range of parameters characterizing the dark matter distribution remain. We find the best choice of parameters, within the range of allowed values, for the surface density of the disk 55 M${}_{\odot }$ pc${}^{-2}$, are the following: the dark matter density at the Galactic center ${\rho }_{DM,c}\approx 100-250$ GeV cm${}^{-3}$, the local dark matter density ${\rho }_{DM}(R_0)\approx 0.56-0.72$ GeV cm${}^{-3}$, and the root-mean-speed of dark matter particles $<v_{DM}^2(R_0){>}^{1/2}\approx 490-550$ km s${}^{-1}$. We also discuss possible astronomical observations that may further limit the range of the allowed models.

46 pages, 9 figures, v2 has significant revisions for clarity and additional analysis to address the uncertainty in the scale length and surface density of the Galactic disk, v3 is updated to match the manuscript accepted by ApJ

References in corpus (11)

• Trigonometric Parallaxes of Massive Star Forming Regions: VI. Galactic Structure, Fundamental Parameters and Non-Circular Motions
• The Milky Way's Circular Velocity Curve to 60 kpc and an Estimate of the Dark Matter Halo Mass from Kinematics of ~2400 SDSS Blue Horizontal Branch Stars
• The Milky Way's circular velocity curve between 4 and 14 kpc from APOGEE data
• On the mass-to-light ratio of the local Galactic disc and the optical luminosity of the Galaxy
• On the local dark matter density
• The stellar halo of the Galaxy
• A First Constraint on the Thick Disk Scale Length: Differential Radial Abundances in K Giants at Galactocentric Radii 4, 8, and 12 kpc
• The Bulge Radial Velocity Assay (BRAVA): I. Techniques and a Rotation Curve
• Milky Way Kinematics: Measurements at the Subcentral Point of the Fourth Quadrant
• Is there a Supermassive Black Hole at the Center of the Milky Way?
• Dynamics of dwarf-spheroidals and the dark matter halo of the Galaxy

Cited by in corpus (8)

• The Besancon Galaxy model renewed I. Constraints on the local star formation history from Tycho data
• Rotation Curve of the Milky Way out to $\sim$ 200 kpc
• Weighing the local dark matter with RAVE red clump stars
• A self-consistent phase-space distribution function for the anisotropic Dark Matter halo of the Milky Way
• The Most Distant Stars in the Milky Way
• How to calculate dark matter direct detection exclusion limits that are consistent with gamma rays from annihilation in the Milky Way halo
• Constraining Dwarf Spheroidal Dark Matter Halos With The Galactic Center Excess
• Kinematics of the Milky way from the statistical analysis of the Gaia Data Release 3