The imprint of dark matter on the Galactic acceleration field

Abstract

Measurements of the accelerations of stars enabled by time-series extreme-precision spectroscopic observations, from pulsar timing, and from eclipsing binary stars in the Solar Neighborhood offer insights into the mass distribution of the Milky Way that do not rely on traditional equilibrium modeling. Given the measured accelerations, we can determine a total mass density, and from this, by accounting for the mass in stars, gas, and dust, we can infer the amount of dark matter. Leveraging the FIRE-2 simulations of Milky Way-mass galaxies, we compare vertical acceleration profiles between cold dark matter (CDM) and self-interacting dark matter (SIDM) with constant cross-section of 1 cm${}^2$ g${}^{-1}$ across three halos with diverse assembly histories. Notably, significant asymmetries in vertical acceleration profiles near the midplane at fixed radii are observed in both CDM and SIDM, particularly in halos recently affected by mergers with satellites of Sagittarius/SMC-like masses or greater. These asymmetries offer a unique window into exploring the merger history of a galaxy. We show that SIDM halos consistently exhibit higher local stellar and dark matter densities and steeper vertical acceleration gradients, up to 30% steeper near the Solar Neighborhood. SIDM halos also manifest a more oblate halo shape in the Solar Neighborhood. Furthermore, enhanced precision in acceleration measurements and larger datasets promise to provide better constraints on the local dark matter density, complementing our understanding from kinematic analysis of their distribution within galaxies.

14 pages, 5 figures, and 2 tables. Submitted to APJ

References in corpus (27)

• Array Programming with NumPy
• Constraints on the Self-Interaction Cross-Section of Dark Matter from Numerical Simulations of the Merging Galaxy Cluster 1E 0657-5
• Are the Magellanic Clouds on their First Passage about the Milky Way?
• ESPRESSO@VLT -- On-sky performance and first results
• Star formation efficiency in galaxy interactions and mergers: a statistical study
• CMasher: Scientific colormaps for making accessible, informative and 'cmashing' plots
• The Vertical Structure of the Outer Milky Way HI Disk
• Dark matter local density determination: recent observations and future prospects
• The Structure and Dynamical Evolution of the Stellar Disk of a Simulated Milky Way-Mass Galaxy
• Public data release of the FIRE-2 cosmological zoom-in simulations of galaxy formation
• Identifying and mitigating noise sources in precision pulsar timing data sets
• A Tail of Two Populations: Chemo-dynamics of the Sagittarius Stream and Implications for its Original Mass
• Planes of satellites around Milky Way/M31-mass galaxies in the FIRE simulations and comparisons with the Local Group
• 3-D gas-phase elemental abundances across the formation histories of Milky Way-mass galaxies in the FIRE simulations: initial conditions for chemical tagging
• Measuring the local dark matter density with LAMOST DR5 and Gaia DR2
• The central densities of Milky Way-mass galaxies in cold and self-interacting dark matter models
• The Milky Way Tomography with SDSS. V. Mapping the Dark Matter Halo
• A measurement of the Galactic plane mass density from binary pulsar accelerations
• Disk settling and dynamical heating: histories of Milky Way-mass stellar disks across cosmic time in the FIRE simulations
• Implications of a time-varying Galactic potential for determinations of the dynamical surface density
• On the stability of tidal streams in action space
• HIDES spectroscopy of bright detached eclipsing binaries from the $Kepler$ field - III. Spectral analysis, updated parameters, and new systems
• Milky Way Accelerometry via Millisecond Pulsar Timing
• Shapes of Milky-Way-Mass Galaxies with Self-Interacting Dark Matter
• Eclipse timing the Milky Way's gravitational potential
• Constraining Self-Interacting Dark Matter with Dwarf Spheroidal Galaxies and High-resolution Cosmological $N$-body Simulations
• Comparing Implementations of Self-Interacting Dark Matter in the Gizmo and Arepo Codes

Cited by in corpus (1)

• Trial by FIRE: Probing the dark matter density profile of dwarf galaxies with GraphNPE