Kinetic Tomography I: A Method for Mapping the Milky Way's Interstellar Medium in Four Dimensions

TL;DR

This paper introduces a novel method for mapping the three-dimensional distribution of the Milky Way's interstellar medium in four dimensions, combining reddening and line emission data to analyze Galactic structure and gas flows.

Contribution

The paper presents a new technique that derives 4D interstellar medium maps using combined reddening and line emission data, validated with known velocities and distances.

Findings

Accurately reproduces line-of-sight velocities of star-forming regions.

Qualitatively agrees with existing Milky Way kinematic models.

Maps will aid in studying gas flows around spiral arms and molecular clouds.

Abstract

We have developed a method for deriving the distribution of the Milky Way's interstellar medium as a function of longitude, latitude, distance and line-of-sight velocity. This method takes as input maps of reddening as a function of longitude, latitude, and distance and maps of line emission as a function of longitude, latitude, and line-of-sight velocity. We have applied this method to datasets covering much of the Galactic plane. The output of this method correctly reproduces the line-of-sight velocities of high-mass star forming regions with known distances from Reid et al. (2014) and qualitatively agrees with results from the Milky Way kinematics literature. These maps will be useful for measuring flows of gas around the Milky Way's spiral arms and into and out of giant molecular clouds.