Deconstructing Disk Velocity Distribution Functions in the Disk-Mass Survey

TL;DR

This paper introduces a new method to measure the radial gradient of the stellar velocity ellipsoid in spiral galaxies, providing insights into galaxy dynamics and mass distribution.

Contribution

It presents a novel technique to determine the radial variation of the velocity ellipsoid ratio in spiral galaxies, a first in the field.

Findings

Measured a radial gradient in the velocity ellipsoid ratio

Achieved 15% error in velocity decomposition at two disk scale-lengths

Enhanced understanding of galaxy kinematics and mass distribution

Abstract

We analyze integral-field ionized gas and stellar line-of-sight kinematics in the context of determining the stellar velocity ellipsoid for spiral galaxies observed by the Disk-Mass Survey. Our new methodology enables us to measure, for the first time, a radial gradient in the ellipsoid ratio sigma_z / sigma_R. Random errors in this decomposition are 15% at two disk scale-lengths.