Kinematics and density of the Galactic spheroid

Abstract

view Abstract Citations (65) References (29) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Kinematics and Density of the Galactic Spheroid Bahcall, J. N. ; Casertano, S. Abstract The authors reanalyze Eggen's proper-motion and radial velocity data for a sample of 94 stars with transverse velocities in excess of 220 km s-1, correcting for observational biases and selection effects by a Monte Carlo analysis of simulated catalogs of proper-motion stars. They obtain a local spheroid number density of n = (9.5±1.3)×10-5pc-3 for 4 ≤ MV ≤ 11 mag. The Eggen catalog yields the following kinematic parameters for the spheroid: an asymmetric drift of 154 km s-1 (corresponding to a rotation velocity ≡66 km s-1), and velocity dispersions in the r, θ, and z directions of 140, 100, and 76 km s-1, respectively. All three of the commonly applied definitions of the spheroid (pressure supported, low metallicity, and geometric distribution) yield consistent results for the density of Population II stars in the vicinity of the Sun. Publication: The Astrophysical Journal Pub Date: September 1986 DOI: 10.1086/164505 Bibcode: 1986ApJ...308..347B Keywords: Galactic Rotation; Kinematics; Radial Velocity; Stellar Motions; Astronomical Catalogs; Density (Mass/Volume); Luminosity; Metallicity; Astrophysics; GALAXIES: INTERNAL MOTIONS; GALAXIES: MILKY WAY; STARS: HIGH-VELOCITY; STARS: PROPER-MOTION; STARS: STELLAR DYNAMICS full text sources ADS |

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