Exploring the Local Milky Way: M Dwarfs as Tracers of Galactic Populations

TL;DR

This study uses a large spectroscopic sample of low-mass stars from SDSS to analyze the kinematic and observable differences between the Milky Way's thin and thick disks, providing insights into their structure and properties.

Contribution

It presents a comprehensive analysis of low-mass dwarfs as tracers of Galactic populations, including velocity dispersions and other observable characteristics, using a large SDSS dataset.

Findings

Velocity dispersions differ between thin and thick disks.

Kinematic distributions align with Galactic models.

Observable properties vary with vertical distance from the Galactic Plane.

Abstract

We have assembled a spectroscopic sample of low-mass dwarfs observed as part of the Sloan Digital Sky Survey along one Galactic sightline, designed to investigate the observable properties of the thin and thick disks. This sample of ~7400 K and M stars also has measured ugriz photometry, proper motions, and radial velocities. We have computed UVW space motion distributions, and investigate their structure with respect to vertical distance from the Galactic Plane. We place constraints on the velocity dispersions of the thin and thick disks, using two-component Gaussian fits. We also compare these kinematic distributions to a leading Galactic model. Finally, we investigate other possible observable differences between the thin and thick disks, such as color, active fraction and metallicity.