Journal
ASTROPHYSICAL JOURNAL
Volume 772, Issue 2, Pages -Publisher
IOP PUBLISHING LTD
DOI: 10.1088/0004-637X/772/2/108
Keywords
Galaxy: kinematics and dynamics; Galaxy: structure; solar neighborhood
Categories
Funding
- NSFC [10903012, 11103034]
- MPG-CAS
- German Research Foundation
- NASA from the Space Telescope Science Institute [HST-HF-51285.01]
- NASA [NAS5-26555]
- Alfred P. Sloan Foundation
- National Science Foundation
- U.S. Department of Energy Office of Science
- University of Arizona
- Brazilian Participation Group
- Brookhaven National Laboratory
- University of Cambridge
- Carnegie Mellon University
- University of Florida
- French Participation Group
- German Participation Group
- Harvard University
- Instituto de Astrofisica de Canarias
- Michigan State/Notre Dame/JINA Participation Group
- Johns Hopkins University
- Lawrence Berkeley National Laboratory
- Max Planck Institute for Astrophysics
- Max Planck Institute for Extraterrestrial Physics
- New Mexico State University
- New York University
- Ohio State University
- Pennsylvania State University
- University of Portsmouth
- Princeton University
- Spanish Participation Group
- University of Tokyo
- University of Utah
- Vanderbilt University
- University of Virginia
- University of Washington
- Yale University
- [Sonderforschungsbereich SFB 881]
Ask authors/readers for more resources
To constrain the Galactic gravitational potential near the Sun (similar to 1.5 kpc), we derive and model the spatial and velocity distributions for a sample of 9000 K-dwarfs with spectra from SDSS/SEGUE, which yield radial velocities and abundances ([Fe/H] and [alpha/Fe]). We first derive the spatial density distribution for three abundance-selected sub-populations of stars accounting for the survey's selection function. The vertical profiles of these sub-populations are simple exponentials and their vertical dispersion profile is nearly isothermal. To model these data, we apply the vertical Jeans equation, which relates the observable tracer number density and vertical velocity dispersion to the gravitational potential or vertical force. We explore a number of functional forms for the vertical force law, fit the dispersion and density profiles of all abundance-selected sub-populations simultaneously in the same potential, and explore all parameter co-variances using a Markov Chain Monte Carlo technique. Our fits constrain a disk mass scale height less than or similar to 300 pc and the total surface mass density to be 67 +/- 6 M-circle dot pc(-2) at vertical bar z vertical bar = 1.0 kpc of which the contribution from all stars is 42 +/- 5 M-circle dot pc(-2) (assuming a contribution from cold gas of 13 M-circle dot pc(-2)). We find significant constraints on the local darkmatter density of 0.0065 +/- 0.0023 M-circle dot pc(-3) (0.25 +/- 0.09 GeV cm(-3)). Together with recent experiments this firms up the best estimate of 0.0075 +/- 0.0021 M-circle dot pc(-3) (0.28 +/- 0.08 GeV cm(-3)), consistent with global fits of approximately round dark matter halos to kinematic data in the outskirts of the Galaxy.
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