Spitzer, Gaia, and the Potential of the Milky Way

Abstract

Near-future data from ESA's Gaia mission will provide precise, full phase-space information for hundreds of millions of stars out to heliocentric distances of ~10 kpc. This "horizon" for full phase-space measurements is imposed by the Gaia parallax errors degrading to worse than 10%, and could be significantly extended by an accurate distance indicator. Recent work has demonstrated how Spitzer observations of RR Lyrae stars can be used to make distance estimates accurate to 2%, effectively extending the Gaia, precise-data horizon by a factor of ten in distance and a factor of 1000 in volume. This Letter presents one approach to exploit data of such accuracy to measure the Galactic potential using small samples of stars associated with debris from satellite destruction. The method is tested with synthetic observations of 100 stars from the end point of a simulation of satellite destruction: the shape, orientation, and depth of the potential used in the simulation are recovered to within a few percent. The success of this simple test with such a small sample in a single debris stream suggests that constraints from multiple streams could be combined to examine the Galaxy's dark matter halo in even more detail --- a truly unique opportunity that is enabled by the combination of Spitzer and Gaia with our intimate perspective on the Galaxy.

6 pages, 5 figures; accepted for publication in ApJ Letters

References in corpus (9)

• The Milky Way Tomography with SDSS: II. Stellar Metallicity
• An Orphan in the "Field of Streams"
• The Origin of the Bifurcation in the Sagittarius Stream
• Kinematics of the stellar halo and the mass distribution of the Milky Way using BHB stars
• Taking the Measure of the Universe: Precision Astrometry with SIM PlanetQuest
• Stream-orbit misalignment I: The dangers of orbit-fitting
• Stream-orbit misalignment II: A new algorithm to constrain the Galactic potential
• The case for OH suppression at near-infrared wavelengths
• Tracing the Orphan Stream to 55 kpc with RR Lyrae Stars

Cited by in corpus (23)

• "Skinny Milky Way, Please", says Sagittarius
• The Hipparcos-Gaia Catalog of Accelerations
• Globular Cluster Streams as Galactic High-Precision Scales - The Poster Child Palomar 5
• WIMPs at the Galactic Center
• Dynamical modeling of tidal streams
• Milky Way Mass and Potential Recovery Using Tidal Streams in a Realistic Halo
• Discovery of a cold stellar stream in the ATLAS DR1 data
• Chaotic Dispersal of Tidal Debris
• Predicted Extension of the Sagittarius Stream to the Milky Way Virial Radius
• Action-space clustering of tidal streams to infer the Galactic potential
• Search for Gamma-ray Emission from Dark Matter Annihilation in the Large Magellanic Cloud with the Fermi Large Area Telescope
• Inferring the gravitational potential of the Milky Way with a few precisely measured stars
• The Gaia-ESO Survey: A globular cluster escapee in the Galactic halo
• Probabilistic model for constraining the Galactic potential using tidal streams
• Kinematics of the Palomar 5 stellar stream from RR Lyrae stars
• Hunting the Parent of the Orphan Stream II: The First High-Resolution Spectroscopic Study
• Predictions for the detection of Tidal Streams with Gaia using Great Circle Methods
• Jeans that fit: weighing the mass of the Milky Way analogues in the $\Lambda \mathrm{CDM}$ universe
• Tidal Debris as a Dark Matter Probe
• Inferring the Galactic potential with Gaia and friends: synergies with other surveys
• Building an Acceleration Ladder with Tidal Streams and Pulsar Timing
• An Orbit Fit to Likely Hermus Stream Stars
• Galactoseismology in the GAIA Era