Giant Cometary HII Regions and Molecular Bow Shocks in Spiral Arms of Galaxies: M83

Abstract

A number of giant cometary HII regions (GCH) sheathed inside molecular bow shocks (MBS) are found along spiral arms of the barred galaxy M83. The open cone structure is explained by a model of expanded HII front in a gaseous arm with steep density gradient, and the bow shock is shown to be formed by encounter of an HII region with the supersonic gas flow across the arm. It is suggested that dual-side compression of molecular gas at the bow head between the MBS and GCH enhances star formation along the spiral arms.

10 pages, 9 figures, to appear in PASJ

References in corpus (9)

• Theory of Star Formation
• Using H-alpha Morphology and Surface Brightness Fluctuations to Age-Date Star Clusters in M83
• An Expanded HST/WFC3 Survey of M83: Project Overview and Targeted Supernova Remnant Search
• Star Cluster Mass and Age Distributions of Two Fields in M83 Based on HST/WFC3 Observations
• ALMA ${}^{12}$CO (J=1--0) imaging of the nearby galaxy M83: Variations in the efficiency of star formation in giant molecular clouds
• Wide-field 12CO (J = 1-0) Imaging of the Nearby Barred Galaxy M83 with NMA and Nobeyema 45-m telescope: Molecular Gas Kinematics and Star Formation Along the Bar
• Molecular Gas Properties in M83 from CO PDFs
• Hydrodynamical models of cometary HII regions
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Cited by in corpus (4)

• Diverse Molecular Structures Across The Whole Star-Forming Disk of M83: High fidelity Imaging at 40pc Resolution
• Study of star clusters in the M83 galaxy with a convolutional neural network
• Molecular Bow Shock in the 3-kpc Norma Arm
• Giant Elephant Trunks from Giant Molecular Clouds