Synthetic Large-Scale Galactic Filaments -- on their Formation, Physical Properties, and Resemblance to Observations

Abstract

Using a population of large-scale filaments extracted from an AREPO simulation of a Milky Way-like galaxy, we seek to understand the extent to which observed large-scale filament properties (with lengths $\gtrsim 100$ pc) can be explained by galactic dynamics alone. From an observer's perspective in the disk of the galaxy, we identify filaments forming purely due to galactic dynamics, without the effects of feedback or local self-gravity. We find that large-scale Galactic filaments are intrinsically rare, and we estimate that at maximum approximately one filament per $\mathrm{kp}{\mathrm{c}}^2$ should be identified in projection, when viewed from the direction of our Sun in the Milky Way. In this idealized scenario, we find filaments in both the arm and interarm regions, and hypothesize that the former may be due to gas compression in the spiral-potential wells, with the latter due to differential rotation. Using the same analysis pipeline applied previously to observations, we analyze the physical properties of large-scale Galactic filaments, and quantify their sensitivity to projection effects and galactic environment (i.e. whether they lie in the arm or interarm regions). We find that observed "Giant Molecular Filaments" are consistent with being non-self-gravitating structures dominated by galactic dynamics. Straighter, narrower, and denser "Bone-like" filaments, like the paradigmatic Nessie filament, have similar column densities, velocity gradients, and Galactic plane heights ($z\approx$ 0 pc) to those in our simple model, but additional physical effects (such as feedback and self-gravity) must be invoked to explain their lengths and widths.

arXiv commentAccepted for publication in The Astrophysical Journal

References in corpus (58)

• The NumPy array: a structure for efficient numerical computation
• Binary companions of evolved stars in APOGEE DR14: Search method and catalog of ~5,000 companions
• E pur si muove: Galiliean-invariant cosmological hydrodynamical simulations on a moving mesh
• From filamentary clouds to prestellar cores to the stellar IMF: Initial highlights from the Herschel Gould Belt survey
• A Multi-Code Analysis Toolkit for Astrophysical Simulation Data
• Characterizing interstellar filaments with Herschel in IC5146
• The Boston University-Five College Radio Astronomy Observatory Galactic Ring Survey
• MAMBO Mapping of Spitzer c2d Small Clouds and Cores
• Structural Analysis of Molecular Clouds: Dendrograms
• The Universality of Turbulence in Galactic Molecular Clouds
• Cores, filaments, and bundles: hierarchical core formation in the L1495/B213 Taurus region
• First GLIMPSE Results on the Stellar Structure of the Galaxy
• VVV DR1: The First Data Release of the Milky Way Bulge and Southern Plane from the Near-Infrared ESO Public Survey VISTA Variables in the Via Lactea
• Physical properties of molecular clouds for the entire Milky Way disk
• Outer structure of the Galactic warp and flare: explaining the Canis Major over-density
• Simulating the formation of molecular clouds. I. Slow formation by gravitational collapse from static initial conditions
• A Parallax-based Distance Estimator for Spiral Arm Sources
• Simulating the formation of molecular clouds. II. Rapid formation from turbulent initial conditions
• The persistent cosmic web and its filamentary structure II: Illustrations
• Hi-GAL, the Herschel infrared Galactic Plane Survey: photometric maps and compact source catalogues. First data release for Inner Milky Way: +68°> l > -70°
• Hierarchical fragmentation and differential star formation in the Galactic "Snake": infrared dark cloud G11.11-0.12
• A Large Catalog of Accurate Distances to Local Molecular Clouds: The Gaia DR2 Edition
• An ALMA study of the Orion Integral Filament: I. Evidence for narrow fibers in a massive cloud
• CO-dark gas and molecular filaments in Milky Way type galaxies
• The "Nessie" Nebula: Cluster Formation in a Filamentary Infrared Dark Cloud
• A Uniform Catalog of Molecular Clouds in the Milky Way
• Gravity or turbulence? II. Evolving column density PDFs in molecular clouds
• Formation and Fragmentation of Gaseous Spurs in Spiral Galaxies
• Galactic cold cores III. General cloud properties
• Large-scale filaments associated with Milky Way spiral arms
• Giant Molecular Filaments in the Milky Way
• The Bones of the Milky Way
• How long does it take to form a molecular cloud?
• Global Modeling of Spur Formation in Spiral Galaxies
• Spurs and feathering in spiral galaxies
• The Galactic warp revealed by Gaia DR2 kinematics
• ATLASGAL -- A Galaxy-wide sample of dense filamentary structures
• Graph-based interpretation of the Molecular Interstellar Medium Segmentation
• The Three-mm Ultimate Mopra Milky Way Survey. I. Survey Overview, Initial Data Releases, and First Results
• The Physical Properties of Large-Scale Galactic Filaments
• The Skeleton of the Milky Way
• Spiral shocks, triggering of star formation and the velocity dispersion in Giant Molecular Clouds
• The Vertical Equilibrium of Molecular Gas in the Galactic Disk
• The integrated properties of the molecular clouds from the JCMT CO(3-2) High Resolution Survey
• A Census of Large-Scale ($\ge$ 10 pc), Velocity-Coherent, Dense Filaments in the Northern Galactic Plane: Automated Identification Using Minimum Spanning Tree
• Simulations of spiral galaxies with an active potential: molecular cloud formation and gas dynamics
• What can simulated molecular clouds tell us about real molecular clouds?
• Giant molecular filaments in the Milky Way II: The fourth Galactic quadrant
• Star-forming content of the giant molecular filaments in the Milky Way
• A 500 pc filamentary gas wisp in the disk of the Milky Way
• The Razor's Edge of Collapse: The Transition Point from Lognormal to Powerlaw in Molecular Cloud PDFs
• RadFil: a Python Package for Building and Fitting Radial Profiles for Interstellar Filaments
• The evolution of Giant Molecular Filaments
• SEDIGISM: The kinematics of ATLASGAL filaments
• Structure and Fragmentation of a high line-mass filament: Nessie
• Supernovae and their host galaxies - IV. The distribution of supernovae relative to spiral arms
• Triggered/sequential star formation? A multi-phase ISM study around the prominent IRDC G18.93-0.03
• The Molecular Structures of Local Arm and Perseus Arm in the Galactic Region of l=[139.75,149.75]${}^{\circ }$, b=[-5.25,5.25]${}^{\circ }$

Cited by in corpus (11)

• The Cloud Factory I: Generating resolved filamentary molecular clouds from galactic-scale forces
• Gaia EDR3 Reveals the Substructure and Complicated Star Formation History of the Greater Taurus-Auriga Star Forming Complex
• A Morphological Classification of 18190 Molecular Clouds Identified in ${}^{12}$CO Data from the MWISP Survey
• OGHReS: Large-scale filaments in the outer Galaxy
• Large-scale Velocity-coherent Filaments in the SEDIGISM Survey: Association with Spiral Arms and Fraction of Dense Gas
• Disconnecting the Dots: Re-Examining the Nature of Stellar "Strings" in the Milky Way
• The Milky Way Atlas for Linear Filaments
• Emergence of high-mass stars in complex fiber networks (EMERGE). I. Early ALMA Survey: observations and massive data reduction
• The Cassiopeia Filament: A Blown Spur of the Local Arm
• Investigations of MWISP Filaments. I. Filament Identification and Analysis Algorithms, and Source Catalogue
• Anisotropy in the carbon monoxide (CO) line emission across the Milky Way's disk