Magnetized interstellar molecular clouds – II. The large-scale structure and dynamics of filamentary molecular clouds
| Autor: | Richard I. Klein, Pak Shing Li |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Physics
Zeeman effect 010308 nuclear & particles physics Turbulence Molecular cloud FOS: Physical sciences Astronomy and Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics Astrophysics Astrophysics - Astrophysics of Galaxies 01 natural sciences Magnetic field symbols.namesake Astrophysics - Solar and Stellar Astrophysics Mean field theory Space and Planetary Science Astrophysics of Galaxies (astro-ph.GA) 0103 physical sciences Perpendicular symbols Infrared dark cloud Magnetohydrodynamics 010303 astronomy & astrophysics Solar and Stellar Astrophysics (astro-ph.SR) Astrophysics::Galaxy Astrophysics |
| Zdroj: | Monthly Notices of the Royal Astronomical Society. 485:4509-4528 |
| ISSN: | 1365-2966 0035-8711 |
| DOI: | 10.1093/mnras/stz653 |
| Popis: | We perform ideal MHD high resolution AMR simulations with driven turbulence and self-gravity and find that long filamentary molecular clouds are formed at the converging locations of large-scale turbulence flows and the filaments are bounded by gravity. The magnetic field helps shape and reinforce the long filamentary structures. The main filamentary cloud has a length of ~4.4 pc. Instead of a monolithic cylindrical structure, the main cloud is shown to be a collection of fiber/web-like sub-structures similar to filamentary clouds such as L1495. Unless the line-of-sight is close to the mean field direction, the large-scale magnetic field and striations in the simulation are found roughly perpendicular to the long axis of the main cloud, similar to 1495. This provides strong support for a large-scale moderately strong magnetic field surrounding L1495. We find that the projection effect from observations can lead to incorrect interpretations of the true three-dimensional physical shape, size, and velocity structure of the clouds. Helical magnetic field structures found around filamentary clouds that are interpreted from Zeeman observations can be explained by a simple bending of the magnetic field that pierces through the cloud. We demonstrate that two dark clouds form a T-shape configuration which are strikingly similar to the Infrared dark cloud SDC13 leading to the interpretation that SDC13 results from a collision of two long filamentary clouds. We show that a moderately strong magnetic field (M_A ~ 1) is crucial for maintaining a long and slender filamentary cloud for a long period of time ~0.5 million years. 21 pages, 21 figure |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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