Molecular envelope around the HII region RCW 120

Abstract

The H II region RCW120 is a well-known object, which is often considered as a target to verify theoretical models of gas and dust dynamics in the interstellar medium. However, the exact geometry of RCW120 is still a matter of debate. In this work, we analyse observational data on molecular emission in RCW120 and show that 13CO(2-1) and C18O(2-1) lines are fitted by a 2D model representing a ring-like face-on structure. The changing of the C18O(3-2) line profile from double-peaked to single-peaked from the dense molecular Condensation 1 might be a signature of stalled expansion in this direction. In order to explain a self-absorption dip of the 13CO(2-1) and 13CO(3-2) lines, we suggest that RCW120 is surrounded by a diffuse molecular cloud, and find confirmation of this cloud on a map of interstellar extinction. Optically thick 13CO(2-1) emission and the infrared 8 um PAH band form a neutral envelope of the H II region resembling a ring, while the envelope breaks into separate clumps on images made with optically thin C18O(2-1) line and far-infrared dust emission.

arXiv commentaccepted to MNRAS

References in corpus (45)

• Astropy: A Community Python Package for Astronomy
• Gaia Data Release 2. Summary of the contents and survey properties
• The SIMBAD astronomical database
• A computer program for fast non-LTE analysis of interstellar line spectra
• A new calibration of stellar parameters of Galactic O stars
• ATLASGAL - The APEX Telescope Large Area Survey of the Galaxy at 870 microns
• SUMSS: A Wide-Field Radio Imaging Survey of the Southern Sky. I. Science goals, survey design and instrumentation
• How to Calculate Molecular Column Density
• The WISE Catalog of Galactic HII Regions
• The Southern Galactic Plane Survey: HI Observations and Analysis
• The Green Bank Telescope HII Region Discovery Survey II. The Source Catalog
• Triggered massive-star formation on the borders of Galactic HII regions. I. A search for `collect and collapse' candidates
• The Milky Way Project First Data Release: A Bubblier Galactic Disk
• Triggered star formation on the borders of the Galactic HII region RCW 120
• Dynamical Expansion of Ionization and Dissociation Front around a Massive Star. II. On the Generality of Triggered Star Formation
• Star formation around RCW 120, the perfect bubble
• Radiation-magnetohydrodynamic simulations of HII regions and their associated PDRs in turbulent molecular clouds
• Molecular Rings and the Thickness of Star-Forming Clouds
• SEDIGISM: Structure, excitation, and dynamics of the inner Galactic interstellar medium
• Star formation triggered by the Galactic HII region RCW 120: First results from the Herschel Space Observatory
• The Milky Way Project: A statistical study of massive star formation associated with infrared bubbles
• StarBench: The D-type expansion of an HII region
• Ionization compression impact on dense gas distribution and star formation, Probability density functions around H ii regions as seen by Herschel
• Near-IR integral field spectroscopy of ionizing stars and young stellar objects on the borders of HII regions
• A self-consistent model of Galactic stellar and dust infrared emission and the abundance of polycyclic aromatic hydrocarbons
• The physical properties of the dust in the RCW 120 HII region as seen by Herschel
• Dusty Wind-Blown Bubbles
• Mopra CO Observations of the Bubble HII Region RCW120
• Distinguishing between HII regions and planetary nebulae with Hi-GAL, WISE, MIPSGAL, and GLIMPSE
• Comparing simulations of ionisation triggered star formation and observations in RCW 120
• Infrared Emission and the Destruction of Dust in HII regions
• Dust dynamics and evolution in expanding HII regions. I. Radiative drift of neutral and charged grains
• Star formation towards the Galactic HII region RCW120
• Dust dynamics and evolution in HII regions - II. Effects of dynamical coupling between dust and gas
• Detecting stellar-wind bubbles through infrared arcs in HII regions
• Molecular Emission Line Formation in Prestellar Cores
• Radiation-pressure-driven dust waves inside bursting interstellar bubbles
• Allsky NICER and NICEST extinction maps based on the 2MASS near-infrared survey
• ALMA observations of RCW 120 Fragmentation at 0.01pc scale
• A systematic study of Galactic infrared bubbles along the Galactic plane with AKARI and Herschel
• RCW 120: A possible case of hit and run, elucidated by multi temperature dust mapping
• Global photometric analysis of galactic HII regions
• Infrared Morphology of Regions of Ionized Hydrogen
• Kinematics of the Galactic Bubble RCW 120
• The Spectral Type of the Ionizing Stars and the Infrared Fluxes of HII Regions

Cited by in corpus (15)

• FEEDBACK: a SOFIA Legacy Program to Study Stellar Feedback in Regions of Massive Star Formation
• HII regions and high-mass starless clump candidates II. Fragmentation and induced star formation at ~0.025 pc scale: An ALMA continuum study
• Self-absorption in [CII], ${}^{12}$CO, and HI in RCW120. Building up a geometrical and physical model of the region
• The role of Galactic HII regions in the formation of filaments. High-resolution submilimeter imaging of RCW 120 with ArTéMiS
• The PDR structure and kinematics around the compact HII regions S235A and S235C with [CII], [13CII], [OI] and HCO+ line profiles
• The KOSMA-$\tau$ PDR Model -- I. Recent updates to the numerical model of photo-dissociated regions
• APEX CO observations towards the photodissociation region of RCW120
• The warm-up phase in massive star-forming cores around RCW 120
• The Role of Magnetic Fields in Triggered Star Formation of RCW 120
• Ethynyl around the HII regions S255 and S257
• Near infrared view on the photodissociation regions S255, S257, NGC7538 and S140
• 3D structure of HII regions in the star-forming complex S254-S258
• The shocked molecular layer in RCW 120
• Gas-phase and Surface Chemistry in the Massive Star-Forming Region RCW\,120
• Stellar feedback and triggered star formation in the prototypical bubble RCW 120