Measuring Fundamental Galactic Parameters with Stellar Tidal Streams and SIM PlanetQuest

Abstract

Extended halo tidal streams from disrupting Milky Way satellites offer new opportunities for gauging fundamental Galactic parameters without challenging observations of the Galactic center. In the roughly spherical Galactic potential tidal debris from a satellite system is largely confined to a single plane containing the Galactic center, so accurate distances to stars in the tidal stream can be used to gauge the Galactic center distance, R_0, given reasonable projection of the stream orbital pole on the X_GC axis. Alternatively, a tidal stream with orbital pole near the Y_GC axis, like the Sagittarius stream, can be used to derive the speed of the Local Standard of Rest (Θ_LSR). Modest improvements in current astrometric catalogues might allow this measurement to be made, but NASA's Space Interferometry Mission (SIM PlanetQuest) can definitively obtain both R_0 and Θ_LSR using tidal streams.

8 pages, 4 figures, accepted for publication in ApJ Letters (minor text revisions). Version with high resolution figures available at http://www.astro.caltech.edu/~drlaw/Papers/GalaxyParameters.pdf

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Cited by in corpus (17)

• Measuring Distance and Properties of the Milky Way's Central Supermassive Black Hole with Stellar Orbits
• The Sagittarius Dwarf Galaxy: a Model for Evolution in a Triaxial Milky Way Halo
• The Milky Way's circular velocity curve between 4 and 14 kpc from APOGEE data
• The total mass of the Large Magellanic Cloud from its perturbation on the Orphan stream
• On the mass-to-light ratio of the local Galactic disc and the optical luminosity of the Galaxy
• Galactic Rotation and Solar Motion from Stellar Kinematics
• Taking the Measure of the Universe: Precision Astrometry with SIM PlanetQuest
• Exploring Halo Substructure with Giant Stars X. Extended Dark Matter or Tidal Disruption?: The Case for the Leo I Dwarf Spheroidal Galaxy
• Metallicity and $\alpha$-element Abundance Gradients along the Sagittarius Stream as Seen by APOGEE
• Galactic Center Research: Manifestations of the Central Black Hole
• Kinematics and Chemistry of Stars Along the Sagittarius Trailing Tidal Tail and Constraints on the Milky Way Mass Distribution
• Identifying Contributions to the Stellar Halo from Accreted, Kicked-Out, and In Situ Populations
• Constraining the Solar Galactic Reflex Velocity Using Gaia Observations of the Sagittarius Stream
• A Deep Proper-Motion Survey in Kapteyn Selected Areas: I. Survey Description and First Results for Stars in the Tidal Tail of Sagittarius and in the Monoceros Ring
• Local Group(s)
• Measuring the Sun's Motion with Stellar Streams
• Precision Astrometry, Galactic Mergers, Halo Substructure and Local Dark Matter