Gas Accretion onto the Milky Way

Abstract

The Milky Way is surrounded by large amounts of gaseous matter that are slowly being accreted over cosmic timescales to support star formation in the disk. The corresponding gas-accretion rate represents a key parameter for the past, present, and future evolution of the Milky Way. In this article, I discuss our current understanding of gas accretion processes in the Galaxy by reviewing past and recent observational and theoretical studies. The first part of this review deals with the spatial distribution of the different gas phases in the Milky Way halo, the origin of the gas, and its total mass. The second part discusses the gas dynamics and the physical processes that regulate the gas flow from the outer Galactic halo to the disk. From the most recent studies follows that the present-day gas accretion rate of the Milky Way is a few solar masses per year, which is sufficient to maintain the Galaxy's star-formation rate at its current level.

33 pages, 7 figures; invited review to appear in Gas Accretion onto Galaxies, Astrophysics and Space Science Library, eds. A. J. Fox & R. Dave, to be published by Springer

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• Giant Gamma-ray Bubbles from Fermi-LAT: AGN Activity or Bipolar Galactic Wind?
• The Search for the Missing Baryons at Low Redshift
• The Vertical Structure of Warm Ionised Gas in the Milky Way
• The present-day star formation rate of the Milky-Way determined from Spitzer detected young stellar objects
• Accretion of gas onto nearby spiral galaxies
• Constraining the Milky Way's Hot Gas Halo with OVII and OVII Emission Lines
• The Vertical Structure of the Outer Milky Way HI Disk
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• X-Ray Absorption from the Milky Way Halo and the Local Group
• An Accurate Distance to High-Velocity Cloud Complex C
• Efficiency of gas cooling and accretion at the disc-corona interface
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• The Source of Ionization along the Magellanic Stream
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• Ionized Gas in the Smith Cloud
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Cited by in corpus (24)

• Streams, substructures and the early history of the Milky Way
• The extent of chemically enriched gas around star-forming dwarf galaxies
• Large Metallicity Variations in the Galactic Interstellar Medium
• The Mass Inflow and Outflow Rates of the Milky Way
• Revealing the Milky Way's Hidden Circumgalactic Medium with the Cosmic Origins Spectrograph Quasar Database for Galactic Absorption Lines
• Chemical Abundances in the Leading Arm of the Magellanic Stream
• Galactic Gas Flows from Halo to Disk: Tomography and Kinematics at the Milky Way's Disk-Halo Interface
• Mass, Morphing, Metallicities: The Evolution of Infalling High Velocity Clouds
• Physical effects on compact high-velocity clouds in the circumgalactic medium
• New constraints on the nature and origin of the Leading Arm of the Magellanic Stream
• The Warm Gas in the MW: A Kinematical Model
• The HI Column Density Distribution of the Galactic Disk and Halo
• Magnetic field draping around clumpy high-velocity clouds in galactic halo
• Circumgalactic gas at its extreme: tidal gas streams around the Whale galaxy NGC 4631 explored with HST/COS
• Exploring Hydrodynamic Instabilities along the Infalling High-Velocity Cloud Complex A
• Hot gas in galaxy halos traced by coronal broad Lyman alpha absorbers
• Cosmological gas accretion history onto the stellar discs of Milky Way-like galaxies in the Auriga simulations -- (I) Temporal dependency
• Insights into the physics when modeling cold gas clouds in a hot plasma
• An Intermediate Velocity HI Cloud Falling to the Galactic Disk; Possible Evidence for Low Metallicity HI Gas Originated Outside the Galactic Disk
• The Long Tails of the Pegasus-Pisces Arch Intermediate Velocity Cloud
• A path towards constraining the evolution of the interstellar medium and outflows in the Milky Way using APOGEE
• Gas accretion onto galaxies and Kelvin-Helmholtz turbulence
• Investigating chemical variations between interstellar gas clouds in the Solar neighbourhood
• Cosmic Rays and Non-thermal Emission Induced by Accretion of Cool Gas onto the Galactic Disk