Molecular cloud distances based on the MWISP CO survey and Gaia DR2

Abstract

We present a new method of calculating distances of molecular clouds in the Galactic plane, using CO observations and the Gaia DR2 parallax and G-band extinction ($A_G$) measurements. Due to the complexity of dust environments in the Galactic plane, $A_G$ contains irregular variations, which is difficult to model. To overcome this difficulty, we propose that the $A_G$ of off-cloud stars (Gaia stars around molecular clouds) can be used as a baseline to calibrate the $A_G$ of on-cloud stars (Gaia stars toward molecular clouds), which removes the $A_G$ components that are unrelated to molecular clouds. The distance is subsequently inferred from the jump point in on-cloud $A_G$ with Bayesian analysis and Markov chain Monte Carlo (MCMC) sampling. We applied this baseline subtraction method to a 100 square degree region (209.75° $\le$ l $\le$ 219.75° and |b| $\le$ 5°) in the third Galactic quadrant, which was mapped as part of the Milky Way Imaging Scroll Painting (MWISP) project, covering three CO isotopologue lines, and derived distances and masses for 11 molecular clouds, including the Maddalena molecular cloud and Sh 2-287. The results indicate that the distance of the Perseus Arm in this region is about 2.4 kpc and molecular clouds are present in the interarm regions.

Accepted for publication in ApJ. 16 pages and 8 figures, extra 10 figures appended

References in corpus (17)

• The Gaia mission
• Theory of Star Formation
• Structural Analysis of Molecular Clouds: Dendrograms
• Gaia-2MASS 3D maps of Galactic interstellar dust within 3 kpc
• A Large Catalog of Accurate Distances to Local Molecular Clouds: The Gaia DR2 Edition
• CO-dark gas and molecular filaments in Milky Way type galaxies
• The Milky Way Imaging Scroll Painting (MWISP): Project Details and Initial Results from the Galactic Longitude of 25.8deg to 49.7deg
• A Large Catalog of Accurate Distances to Molecular Clouds from PS1 Photometry
• Identification of Young Stellar Object candidates in the $Gaia$ DR2 x AllWISE catalogue with machine learning methods
• The local spiral structure of the Milky Way
• V838 Monocerotis: A Geometric Distance from Hubble Space Telescope Polarimetric Imaging of its Light Echo
• A Possible Extension of the Scutum-Centaurus Arm into the Outer Second Quadrant
• The Distances to Molecular Clouds at High Galactic Latitudes based on GAIA DR2
• Parallaxes for star forming regions in the inner Perseus spiral arm
• Molecular Lines of 13 Galactic Infrared Bubble Regions
• Extended CO emission in the field of the light echo of V838 Mon
• Molecular gas toward the Gemini OB1 Giant Molecular Cloud Complex I: Observation data

Cited by in corpus (14)

• A detailed characterization of HR 8799's debris disk with ALMA in Band 7
• Distances and statistics of local molecular clouds in the first Galactic quadrant
• The spiral structure in the Solar neighborhood
• Distances to molecular clouds in the second Galactic quadrant
• Gas Column Density Distribution of Molecular Clouds in the Third Quadrant of the Milky Way
• Two-component Magnetic Field along the Line of Sight to the Perseus Molecular Cloud: Contribution of the Foreground Taurus Molecular Cloud
• Distances to nearby molecular clouds traced by young stars
• On the Beam Filling Factors of Molecular Clouds
• Improved Measurements of Molecular Cloud Distances Based on Global Search
• Role of Filamentary Structures in the Formation of Two Dense Cores, L1544 and L694-2
• The distances to molecular clouds in the fourth Galactic quadrant
• A Herschel study of G214.5-1.8: a young, cold and quiescent giant molecular filament on the shell of a HI superbubble
• New method for estimating molecular cloud distances based on Gaia, 2MASS, and the TRILEGAL galaxy model
• CU-JADE: A Method for Traversing Extinction Jumps along the Line of Sight