Towards a direct measure of the Galactic acceleration

Abstract

High precision spectrographs can enable not only the discovery of exoplanets, but can also provide a fundamental measurement in Galactic dynamics. Over about ten year baselines, the expected change in the line-of-sight velocity due to the Galaxy's gravitational field for stars at $\sim$ kpc scale distances above the Galactic mid-plane is $\sim$ few - 10 cm/s, and may be detectable by the current generation of high precision spectrographs. Here, we provide theoretical expectations for this measurement based on both static models of the Milky Way and isolated Milky Way simulations, as well from controlled dynamical simulations of the Milky Way interacting with dwarf galaxies. We simulate a population synthesis model to analyze the contribution of planets and binaries to the Galactic acceleration signal. We find that while low-mass, long-period planetary companions are a contaminant to the Galactic acceleration signal, their contribution is very small. Our analysis of $\sim$ ten years of data from the LCES HIRES/Keck precision radial velocity (RV) survey shows that slopes of the RV curves of standard RV stars agree with expectations of the local Galactic acceleration near the Sun within the errors, and that the error in the slope scales inversely as the square root of the number of observations. Thus, we demonstrate that a survey of stars with low intrinsic stellar jitter at kpc distances above the Galactic mid-plane for realistic sample sizes can enable a direct determination of the dark matter density.

arXiv commentaccepted to ApJ Letters

References in corpus (38)

• Gaia Data Release 2. Summary of the contents and survey properties
• Observational evidence for self-interacting cold dark matter
• galpy: A Python Library for Galactic Dynamics
• The merger that led to the formation of the Milky Way's inner stellar halo and thick disk
• Dark Matter Self-interactions and Small Scale Structure
• Detection of the gravitational redshift in the orbit of the star S2 near the Galactic centre massive black hole
• A dynamically young and perturbed Milky Way disk
• The Gemini Planet Imager Exoplanet Survey: Giant Planet and Brown Dwarf Demographics From 10-100 AU
• The LCES HIRES/Keck Precision Radial Velocity Exoplanet Survey
• The Local Dark Matter Density
• The dark matter density at the Sun's location
• State of the Field: Extreme Precision Radial Velocities
• Radial Velocity Jitter in Stars from the California and Carnegie Planet Search at Keck Observatory
• The local density of matter mapped by Hipparcos
• Quasi-linear formulation of MOND
• Stars, Gas, and Dark Matter in the Solar Neighborhood
• Gaia DR2 Proper Motions of Dwarf Galaxies within 420 kpc: Orbits, Milky Way Mass, Tidal Influences, Planar Alignments, and Group Infall
• Rings and Radial Waves in the Disk of the Milky Way
• The Vertical Structure of the Outer Milky Way HI Disk
• Mass and shape of the Milky Way's dark matter halo with globular clusters from Gaia and Hubble
• Constraining the Galaxy's dark halo with RAVE stars
• The Space Motion of Leo I: The Mass of the Milky Way's Dark Matter Halo
• Evidence for an Intermediate-Mass Milky Way from Gaia DR2 Halo Globular Cluster Motions
• The total stellar halo mass of the Milky Way
• Resolving the Metallicity Distribution of the Stellar Halo with the H3 Survey
• The Role of Gas In Maintaining Quasi-Steady Spiral Structure In Stellar Disks
• Dark matter halo shapes in the Auriga simulations
• Astrophysical Insights into Radial Velocity Jitter from an Analysis of 600 Planet-search Stars
• Trojans in the Solar Neighborhood
• Implications of a time-varying Galactic potential for determinations of the dynamical surface density
• Predicting radial-velocity jitter induced by stellar oscillations based on Kepler data
• Tidal Imprints of a Dark Sub-Halo on the Outskirts of the Milky Way II. Perturber Azimuth
• Stellar Accelerations and the Galactic Gravitational Field
• The dynamical matter density in the solar neighbourhood inferred from Gaia DR1
• Mapping the galactic gravitational potential with peculiar acceleration
• Probing Dark Matter Using Precision Measurements of Stellar Accelerations
• Antlia2's role in driving the ripples in the outer gas disk of the Galaxy
• Properties of F Stars with Stable Radial Velocity Timeseries: A Useful Metric for Selecting Low-jitter F Stars

Cited by in corpus (15)

• Dark matter local density determination: recent observations and future prospects
• Gaia Early Data Release 3: Acceleration of the solar system from Gaia astrometry
• The effect of the deforming dark matter haloes of the Milky Way and the Large Magellanic Cloud on the Orphan-Chenab stream
• Eclipse timing the Milky Way's gravitational potential
• Deep Potential: Recovering the gravitational potential from a snapshot of phase space
• The Milky Way, Coming into Focus: Precision Astrometry Probes its Evolution, and its Dark Matter
• Charting Galactic Accelerations with Stellar Streams and Machine Learning
• A Pulsar-Based Map of Galactic Acceleration
• Quantifying the influence of bars on action-based dynamical modelling of disc galaxies
• Prospects for probing small-scale dark matter models with pulsars around Sagittarius A*
• The imprint of dark matter on the Galactic acceleration field
• Building an Acceleration Ladder with Tidal Streams and Pulsar Timing
• Weighing the Darkness III: How Gaia Could, but Probably Won't, Astrometrically Detect Free-Floating Black Holes
• The Galactic potential and dark matter density from angular stellar accelerations
• Charting galactic accelerations II: how to 'learn' accelerations in the solar neighbourhood