Autonomous Gaussian decomposition of the Galactic Ring Survey. II. The Galactic distribution of 13CO

Abstract

Knowledge about the distribution of CO emission in the Milky Way is essential to understand the impact of Galactic environment on the formation and evolution of structures in the interstellar medium. However, currently our insight about the fraction of CO in spiral arm and interarm regions is still limited by large uncertainties in assumed rotation curve models or distance determination techniques. In this work we use a Bayesian approach to obtain the current best assessment of the distribution of 13CO from the Galactic Ring Survey. We performed two different distance estimates that either included or excluded a model for Galactic features. We also include a prior for the solution of the kinematic distance ambiguity that was determined from a compilation of literature distances and an assumed size-linewidth relationship. We find that the fraction of 13CO emission associated with spiral arm features varies from 76% to 84% between the two distance runs. The vertical distribution of the gas is concentrated around the Galactic midplane showing FWHM values of ~75 pc. We do not find any significant difference between gas emission properties associated with spiral arm and interarm features. In particular the distribution of velocity dispersion values of gas emission in spurs and spiral arms is very similar. We detect a trend of higher velocity dispersion values with increasing heliocentric distance, which we attribute to beam averaging effects caused by differences in spatial resolution. We argue that the true distribution of the gas emission is likely more similar to a combination of our two distance results, and highlight the importance of using complementary distance estimations to safeguard against the pitfalls of any single approach. We conclude that the methodology presented in this work is a promising way to determine distances to gas emission features in Galactic plane surveys.

arXiv commentAccepted for publication in A&A. 27 pages, 31 figures (main text: 18 pages, 21 figures). The PDF contains multi-layer figures that can be displayed with Adobe Acrobat. Table 2 with the distance results is available in its entirety at the CDS. The Python wrapper for the Bayesian Distance Calculator (BD_wrapper) is freely available at GitHub under https://github.com/mriener/BD_wrapper

References in corpus (67)

• Astropy: A Community Python Package for Astronomy
• The Milky Way in Molecular Clouds: A New Complete CO Survey
• The Galaxy in Context: Structural, Kinematic and Integrated Properties
• Trigonometric Parallaxes of High Mass Star Forming Regions: the Structure and Kinematics of the Milky Way
• Trigonometric Parallaxes of Massive Star Forming Regions: VI. Galactic Structure, Fundamental Parameters and Non-Circular Motions
• A geometric distance measurement to the Galactic Center black hole with 0.3% uncertainty
• Trigonometric Parallaxes Of High-Mass Star Forming Regions: Our View Of The Milky Way
• Re-examining Larson's Scaling Relationships in Galactic Molecular Clouds
• The Boston University-Five College Radio Astronomy Observatory Galactic Ring Survey
• The WISE Catalog of Galactic HII Regions
• Physical properties of molecular clouds for the entire Milky Way disk
• ATLASGAL --- properties of a complete sample of Galactic clumps
• A Parallax-based Distance Estimator for Spiral Arm Sources
• The PdBI Arcsecond Whirlpool Survey (PAWS): Environmental Dependence of Giant Molecular Cloud Properties in M51
• The Bolocam Galactic Plane Survey -- II. Catalog of the Image Data
• Kinematic Distances to Molecular Clouds identified in the Galactic Ring Survey
• Molecular gas kinematics within the central 250 pc of the Milky Way
• Ammonia from cold high-mass clumps discovered in the inner Galactic disk by the ATLASGAL survey
• A Catalog of MSX Infrared Dark Cloud Candidates
• FOREST Unbiased Galactic plane Imaging survey with the Nobeyama 45-m telescope (FUGIN) I: Project Overview and Initial Results
• The Milky Way Imaging Scroll Painting (MWISP): Project Details and Initial Results from the Galactic Longitude of 25.8deg to 49.7deg
• Properties of Hi-GAL clumps in the inner Galaxy]{The Hi-GAL compact source catalogue. I. The physical properties of the clumps in the inner Galaxy ($-71.0^{\circ }<\ell <67.0^{\circ }$)
• A Uniform Catalog of Molecular Clouds in the Milky Way
• Resolution of the Distance Ambiguity for Galactic HII Regions
• The Bones of the Milky Way
• The Bolocam Galactic Plane Survey IX: Data Release 2 and Outer Galaxy Extension
• The linewidth-size relationship in the dense ISM of the Central Molecular Zone
• CHIMPS: the ${}^{13}$CO/C${}^{18}$O (J=3-2) Heterodyne Inner Milky Way Plane Survey
• Kinematic Distances: A Monte Carlo Method
• Galactic Supernova Remnant Candidates Discovered by THOR
• ATLASGAL --- Complete compact source catalogue: 280\degr\ $<\ell <$ 60\degr
• 'The Brick' is not a brick: A comprehensive study of the structure and dynamics of the Central Molecular Zone cloud G0.253+0.016
• The Bolocam Galactic Plane Survey. XIV. Physical Properties of Massive Starless and Star Forming Clumps
• Molecular clouds and clumps in the Boston University-Five College Radio Astronomy Observatory Galactic Ring Survey
• The First VERA Astrometry Catalog
• Star formation in Galactic spiral arms and the inter-arm regions
• Distribution and mass of diffuse and dense CO gas in the Milky Way
• The Dense Gas Mass Fraction of Molecular Clouds in the Milky Way
• GaussPy+: A fully automated Gaussian decomposition package for emission line spectra
• The Hi-GAL catalogue of dusty filamentary structures in the Galactic Plane
• The Molecular Properties of Galactic HII Regions
• The integrated properties of the molecular clouds from the JCMT CO(3-2) High Resolution Survey
• Star formation towards the Scutum tangent region and the effects of Galactic environment
• What can simulated molecular clouds tell us about real molecular clouds?
• Revised Distances to 21 Supernova Remnants
• New Distances to Four Supernova Remnants
• The spiral structure of the Milky Way
• The HI/OH/Recombination line survey of the inner Milky Way (THOR): data release 2 and HI overview
• The Effect of Spiral Arms on Star Formation in the Galaxy
• A guided map to the Spiral arms in the galactic disk of the Milky Way
• The Bolocam Galactic Plane Survey. VIII. A Mid-Infrared Kinematic Distance Discrimination Method
• CHIMPS: Physical properties of molecular clumps across the inner Galaxy
• Distribution and characteristics of Infrared Dark Clouds using genetic forward modelling
• The Bolocam Galactic Plane Survey. XII. Distance Catalog Expansion Using Kinematic Isolation of Dense Molecular Cloud Structures With 13CO(1-0)
• Star formation scales and efficiency in Galactic spiral arms
• Galactic Rotation from Cepheids with Gaia DR2 and Effects of Non-Axisymmetry
• Gaia-DR2 extended kinematical maps. Part I: Method and application
• The prevalence of star formation as a function of Galactocentric radius
• Errors in kinematic distances and our image of the Milky Way Galaxy
• A Galactic Plane Defined by the Milky Way HII Region Distribution
• The role of spiral arms in Milky Way star formation
• Autonomous Gaussian decomposition of the Galactic Ring Survey. I. Global statistics and properties of the 13CO emission data
• Evolutionary Models for 15 Galactic Supernova Remnants with New Distances
• Distances to Supernova Remnants G$20.4+0.1$, G$24.7-0.6$ and G$28.6-0.1$ and New Molecular Cloud Associations
• Structured Molecular Gas Reveals Galactic Spiral Arms
• Streaming Motions and Kinematic Distances to Molecular Clouds
• Large-scale latitude distortions of the inner Milky Way Disk from the Herschel/Hi-GAL Survey

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• Giant Molecular Cloud Catalogues for PHANGS-ALMA: Methods and Initial Results
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