Molecular Clouds in the Galactic Plane from $l$ = [59.75${}^{\circ }$, 74.75${}^{\circ }$] and $b$ = [$-$5.25${}^{\circ }$, +5.25${}^{\circ }$]

Abstract

In this paper we present the distribution of molecular gas in the Milky Way Galactic plane from $l$ = [59.75, 74.75]${}^{\circ }$ and $b$ = [$-$5.25, +5.25]${}^{\circ }$, using the MWISP ${}^{12}$CO/${}^{13}$CO/${\mathrm{C}}^{18}\mathrm{O}$ emission line data. The molecular gas in this region can be mainly attributed to the Local spur, Local arm, Perseus arm, and Outer arm. Statistics of the physical properties of the molecular gas in each arm, such as excitation temperature, optical depth, and column density, are presented. Using the DBSCAN algorithm, we identified 15 extremely distant molecular clouds with kinematic distances of 14.72$-$17.77 kpc and masses of 363$-$520 M${}_{\odot }$, which we find could be part of the Outer Scutum-Centaurus (OSC) arm identified by \cite{2011ApJ...734L..24D} and \cite{2015ApJ...798L..27S}. It is also possible that, 12 of these 15 extremely distant molecular clouds constitute an independent structure between the Outer and the OSC arms or a spur. There exist two Gaussian components in the vertical distribution of the molecular gas in the Perseus spiral arm. These two Gaussian components correspond to two giant filaments parallel to the Galactic plane. We find an upward warping of the molecular gas in the Outer spiral arm with a displacement of around 270 pc with respect to the Galactic mid-plane.

33 pages, 19 figures

References in corpus (13)

• Trigonometric Parallaxes Of High-Mass Star Forming Regions: Our View Of The Milky Way
• On the Star Formation Efficiency of Turbulent Magnetized Clouds
• On the Density Distribution in Star-forming Interstellar Clouds
• A Large Catalog of Accurate Distances to Local Molecular Clouds: The Gaia DR2 Edition
• 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
• The SEDIGISM survey: first data release and overview of the Galactic structure
• A Possible Extension of the Scutum-Centaurus Arm into the Outer Second Quadrant
• Distances and statistics of local molecular clouds in the first Galactic quadrant
• Molecular Clouds in the Second Quadrant of the Milky Way Mid-plane from l$=$104$.{}^{\circ }$75 to l=119$.{}^{\circ }$75 and b=$-$5$.{}^{\circ }$25 to b=5$.{}^{\circ }$25
• Gas Column Density Distribution of Molecular Clouds in the Third Quadrant of the Milky Way
• The discovery of the largest gas filament in our Galaxy, or a new spiral arm?
• On the Spatial Distribution of ${}^{13}$CO Structures within ${}^{12}$CO Molecular Clouds