Formation of Structure in Molecular Clouds: A Case Study

Abstract

Molecular clouds (MCs) are highly structured and ``turbulent''. Colliding gas streams of atomic hydrogen have been suggested as a possible source of MCs, imprinting the filamentary structure as a consequence of dynamical and thermal instabilities. We present a 2D numerical analysis of MC formation via converging HI flows. Even with modest flow speeds and completely uniform inflows, non-linear density perturbations as possible precursors of MCs arise. Thus, we suggest that MCs are inevitably formed with substantial structure, e.g., strong density and velocity fluctuations, which provide the initial conditions for subsequent gravitational collapse and star formation in a variety of galactic and extragalactic environments.

4 pages, 5 figures, resubmitted to ApJL

References in corpus (11)

• Control of star formation by supersonic turbulence
• Interstellar Turbulence I: Observations and Processes
• Thermal condensation in a turbulent atomic hydrogen flow
• Flows, Fragmentation, and Star Formation. I. Low-mass Stars in Taurus
• Molecular Cloud Formation Behind Shock Waves
• Collapse and Fragmentation in Finite Sheets
• Towards simulating star formation in the interstellar medium
• The Field Condition: A New Constraint of Spatial Resolution in Simulations of the nonlinear Development of Thermal Instability
• Turbulent Ambipolar Diffusion: Numerical Studies in 2D
• Protostellar collapse induced by compression. II: rotation and fragmentation
• Scaling Relations for Turbulence in the Multiphase Interstellar Medium

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• Rapid Molecular Cloud and Star Formation: Mechanisms and Movies
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• Giant Molecular Clouds in the Local Group Galaxy M33
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• The Virial Balance of Clumps and Cores in Molecular Clouds
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• A Model for the Onset of Self-gravitation and Star Formation in Molecular Gas Governed by Galactic Forces: I. Cloud-scale Gas Motions
• Two-Fluid MHD Simulations of Converging Hi Flows in the Interstellar Medium. II: Are Molecular Clouds Generated Directly from Warm Neutral Medium?
• The Turbulence Spectrum of Molecular Clouds in the Galactic Ring Survey: A Density-Dependent PCA Calibration
• Molecular Cloud Evolution V. Cloud Destruction by Stellar Feedback
• On the structure of the turbulent interstellar atomic hydrogen. I- Physical characteristics
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• ATOMS: ALMA Three-millimeter Observations of Massive Star-forming regions -- XI. From inflow to infall in hub-filament systems
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• Understanding star formation in molecular clouds IV. Column density PDFs from quiescent to massive molecular clouds
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• Supernova Feedback in Molecular Clouds: Global Evolution and Dynamics
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• The Effects of Inhomogeneities within Colliding Flows on the Formation and Evolution of Molecular Clouds
• The Interstellar Medium and Star Formation of Galactic Disks. I. ISM and GMC properties with Diffuse FUV and Cosmic Ray Backgrounds
• Colliding Clouds: The Star Formation Trigger of the Stellar Cluster Around BD+40 4124
• Dense Regions in Supersonic Isothermal Turbulence
• Local Molecular Gas toward the Aquila Rift Region
• MHD Stability of ISM Phase Transition Layers I: Magnetic Field Orthogonal to Front
• Self-Sustained Turbulence without Dynamical Forcing: A Two-Dimensional Study of a Bistable Interstellar Medium
• Submillimeter Polarimetry with PolKa, a reflection-type modulator for the APEX telescope
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• Expanding Shell and Star Formation in the Infrared Dust Bubble N6
• Formation of Massive Star Clusters by Fast HI Gas Collision
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• Molecular Clouds: Internal Properties, Turbulence, Star Formation and Feedback
• Gravity or turbulence V: Star forming regions undergoing violent relaxation
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