Autonomous Gaussian decomposition of the Galactic Ring Survey I. Global statistics and properties of the (CO)-C-13 emission data
Artikel i vetenskaplig tidskrift, 2019

The analysis of large molecular line surveys of the Galactic plane is essential for our understanding of the gas kinematics on Galactic scales and, in particular, its link with the formation and evolution of dense structures in the interstellar medium. An approximation of the emission peaks with Gaussian functions allows for an efficient and straightforward extraction of useful physical information contained in the shape and Doppler-shifted frequency of the emission lines contained in these enormous data sets. In this work, we present an overview and the first results of a Gaussian decomposition of the entire Galactic Ring Survey (GRS) (CO)-C-13 (1-0) data that consists of about 2.3 million spectra. We performed the decomposition with the fully automated GAUSSPY+ algorithm and fitted about 4.6 million Gaussian components to the GRS spectra. These decomposition results enable novel and unexplored ways to interpret and study the gas velocity structure. We discuss the statistics of the fit components and relations between the fitted intensities, velocity centroids, and velocity dispersions. We find that the magnitude of the velocity dispersion values increase towards the inner Galaxy and around the Galactic midplane, which we speculate is partly due to the influence of the Galactic bar and regions with higher non-thermal motions located in the midplane, respectively. We also used our decomposition results to infer global properties of the gas emission and find that the number of fit components used per spectrum is indicative of the amount of structure along the line of sight. We find that the emission lines from regions located on the far side of the Galaxy show increased velocity dispersion values, which are likely due to beam averaging effects. We demonstrate how this trend has the potential to aid in characterising Galactic structure by disentangling emission that belongs to the nearby Aquila Rift molecular cloud from emission that is more likely associated with the Perseus and Outer spiral arms. With this work, we also make our entire decomposition results available.

radio lines: general

ISM: lines and bands

methods: data analysis

ISM: kinematics and dynamics

Författare

M. Riener

Universität Heidelberg

Max-Planck-Gesellschaft

Jouni Kainulainen

Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik, Galaktisk astrofysik

H. Beuther

Max-Planck-Gesellschaft

J. D. Henshaw

Max-Planck-Gesellschaft

Jan Orkisz

Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik, Galaktisk astrofysik

Y. Wang

Max-Planck-Gesellschaft

Astronomy and Astrophysics

0004-6361 (ISSN) 1432-0746 (eISSN)

Vol. 633 A14

Ämneskategorier

Astronomi, astrofysik och kosmologi

Atom- och molekylfysik och optik

Geofysik

DOI

10.1051/0004-6361/201936814

Mer information

Senast uppdaterat

2020-02-11