The evolution of Giant Molecular Filaments

Abstract

In recent years there has been a growing interest in studying giant molecular filaments (GMFs), which are extremely elongated (> 100pc in length) giant molecular clouds (GMCs). They are often seen as inter-arm features in external spiral galaxies, but have been tentatively associated with spiral arms when viewed in the Milky Way. In this paper, we study the time evolution of GMFs in a high-resolution section of a spiral galaxy simulation, and their link with spiral arm GMCs and star formation, over a period of 11Myrs. The GMFs generally survive the inter-arm passage, although they are subject to a number of processes (e.g. star formation, stellar feedback and differential rotation) which can break the giant filamentary structure into smaller sections. The GMFs are not gravitationally bound clouds as a whole, but are, to some extent, confined by external pressure. Once they reach the spiral arms, the GMFs tend to evolve into more substructured spiral arm GMCs, suggesting that GMFs may be precursors to arm GMCs. Here, they become incorporated into the more complex and almost continuum molecular medium that makes up the gaseous spiral arm. Instead of retaining a clear filamentary shape, their shapes are distorted both by their climb up the spiral potential and their interaction with the gas within the spiral arm. The GMFs do tend to become aligned with the spiral arms just before they enter them (when they reach the minimum of the spiral potential), which could account for the observations of GMFs in the Milky Way.

15 pages, 11 figures, MNRAS accepted

References in corpus (17)

• SPLASH: An interactive visualisation tool for Smoothed Particle Hydrodynamics simulations
• Dynamically Driven Evolution of the Interstellar Medium in M51
• Large-scale filaments associated with Milky Way spiral arms
• The Bones of the Milky Way
• GMC formation by agglomeration and self gravity
• The formation of molecular clouds in spiral galaxies
• The Blueshifting and Baldwin effects for the [OIII] 5007 Emission Line in Type 1 Active Galactic Nuclei
• Spurs and feathering in spiral galaxies
• An HST Archival Survey of Feathers in Spiral Galaxies
• A Census of Large-Scale ($\ge$ 10 pc), Velocity-Coherent, Dense Filaments in the Northern Galactic Plane: Automated Identification Using Minimum Spanning Tree
• The morphology of the Milky Way - I. Reconstructing CO maps from simulations in fixed potentials
• The PdBI Arcsecond Whirlpool Survey (PAWS). The Role of Spiral Arms in Cloud and Star Formation
• The Interstellar Medium and star formation on kpc size scales
• The morphology of the Milky Way - II. Reconstructing CO maps from disc galaxies with live stellar distributions
• Eventful Evolution of Giant Molecular Clouds in Dynamically Evolving Spiral Arms
• Detection of Dense Molecular Gas in Inter-Arm Spurs in M51
• Spiral Density Waves in M81. II. Hydrodynamic Simulations for Gas Response to Stellar Spiral Density Waves

Cited by in corpus (12)

• The Cloud Factory I: Generating resolved filamentary molecular clouds from galactic-scale forces
• The integrated properties of the molecular clouds from the JCMT CO(3-2) High Resolution Survey
• The SEDIGISM survey: Molecular clouds in the inner Galaxy
• UV to submillimetre luminosity functions of TNG50 galaxies
• Comparing the Properties of GMCs in M33 from Simulations and Observations
• Synthetic Large-Scale Galactic Filaments -- on their Formation, Physical Properties, and Resemblance to Observations
• Atomic and molecular gas properties during cloud formation
• Probing the massive star forming environment - a multiwavelength investigation of the filamentary IRDC G333.73+0.37
• On the evolution of the observed Mass-to-Length relationship for star-forming filaments
• Weather Forecast of the Milky Way: Shear and Stellar feedback determine the lives of Galactic-scale filaments
• A Herschel study of G214.5-1.8: a young, cold and quiescent giant molecular filament on the shell of a HI superbubble
• Bimodal orientation distribution and head-tail asymmetry of a sample of filamentary molecular clouds