The simulation of molecular clouds formation in the Milky Way

Abstract

Using 3D hydrodynamic calculations we simulate formation of molecular clouds in the Galaxy. The simulations take into account molecular hydrogen chemical kinetics, cooling and heating processes. Comprehensive gravitational potential accounts for contributions from the stellar bulge, two and four armed spiral structure, stellar disk, dark halo and takes into account self-gravitation of the gaseous component. Gas clouds in our model form in the spiral arms due to shear and wiggle instabilities and turn into molecular clouds after $t\simgt 100$ Myr. At the times $t\sim 100-300$ Myr the clouds form hierarchical structures and agglomerations with the sizes of 100 pc and greater. We analyze physical properties of the simulated clouds and find that synthetic statistical distributions like mass spectrum, "mass-size" relation and velocity dispersion are close to those observed in the Galaxy. The synthetic $l-v$ (galactic longitude - radial velocity) diagram of the simulated molecular gas distribution resembles observed one and displays a structure with appearance similar to Molecular Ring of the Galaxy. Existence of this structure in our modelling can be explained by superposition of emission from the galactic bar and the spiral arms at $\sim$3-4 kpc.

10 pages, 8 figures

References in corpus (15)

• Theory of Star Formation
• Star Formation in Disk Galaxies. I. Formation and Evolution of Giant Molecular Clouds via Gravitational Instability and Cloud Collisions
• The Nature of the Dense Core Population in the Pipe Nebula: Thermal Cores Under Pressure
• The Spiral Structure of the Outer Milky Way in Hydrogen
• Gas flow models in the Milky Way embedded bars
• Formation of Spiral-Arm Spurs and Bound Clouds in Vertically Stratified Galactic Gas Disks
• GMC formation by agglomeration and self gravity
• The formation of molecular clouds in spiral galaxies
• Spurs and feathering in spiral galaxies
• The X-factor in Galaxies: I. Dependence on Environment and Scale
• Molecular clouds and clumps in the Boston University-Five College Radio Astronomy Observatory Galactic Ring Survey
• Star formation around the HII region Sh2-235
• Deep Near-Infrared Survey of the Pipe Nebula II: Data, Methods, and Dust Extinction Maps
• The Myth of the Molecular Ring
• A Simple Perspective on the Mass-Area Relationship in Molecular Clouds

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