Mixing between High Velocity Clouds and the Galactic Halo

Abstract

In the Galactic halo, metal-bearing Galactic halo material mixes into high velocity clouds (HVCs) as they hydrodynamically interact. This interaction begins long before the clouds completely dissipate and long before they slow to the velocity of the Galactic material. In order to make quantitative estimates of the mixing efficiency and resulting metal enrichment of HVCs, we made detailed 2 and 3 dimensional simulations of cloud-ISM interactions. Our simulations track the hydrodynamics and time dependent ionization levels. They assume that the cloud originally has a warm temperature and extremely low metallicity while the surrounding medium has a high temperature, low density, and substantial metallicity, but our simulations can be generalized to other choices of initial metallicities. In our simulations, mixing between cloud and halo gas noticeably raises the metallicity of the high velocity material. We present plots of the mixing efficiency and metal enrichment as a function of time.

References in corpus (19)

• Where are the missing galactic satellites?
• Gaseous Galaxy Halos
• Highly-Ionized High-Velocity Gas in the Vicinity of the Galaxy
• Distances and Metallicities of High- and Intermediate-Velocity Clouds
• Complex C: A Low-Metallicity High-Velocity Cloud Plunging into the Milky Way
• The Fate of High-Velocity Clouds: Warm or Cold Cosmic Rain?
• A Large Reservoir of Ionized Gas in the Galactic Halo: Ionized Silicon in High-Velocity and Intermediate-Velocity Clouds
• A Catalog of Ultra-compact High Velocity Clouds from the ALFALFA Survey: Local Group Galaxy Candidates?
• The mode of gas accretion onto star-forming galaxies
• Metallicity and Ionization in High Velocity Cloud Complex C
• Gas Accretion is Dominated by Warm Ionized Gas in Milky Way-Mass Galaxies at z ~ 0
• Simulations of High-Velocity Clouds. I. Hydrodynamics and High-Velocity High Ions
• A Very Sensitive 21cm Survey for Galactic High-Velocity HI
• Hubble Space Telescope Survey of Interstellar High-Velocity Si III
• Ionized Gas in the Smith Cloud
• Hubble-COS Observations of Galactic High-Velocity Clouds: Four AGN Sight Lines through Complex C
• Physical Properties of Complex C Halo Clouds
• Arecibo imaging of compact high-velocity clouds
• The Evolution of Gas Clouds Falling in the Magnetized Galactic Halo: High Velocity Clouds (HVCs) Originated in the Galactic Fountain

Cited by in corpus (18)

• A Characteristic Scale for Cold Gas
• Large Metallicity Variations in the Galactic Interstellar Medium
• On the Metallicity and Origin of the Smith High-Velocity Cloud
• Cloudy with A Chance of Rain: Accretion Braking of Cold Clouds
• Chemical Abundances in the Leading Arm of the Magellanic Stream
• About Metallicity Variations in the Local Galactic Interstellar Medium
• Mass, Morphing, Metallicities: The Evolution of Infalling High Velocity Clouds
• Simulating Gas Inflow at the Disk-Halo Interface
• The Smith Cloud: surviving a high speed transit of the Galactic disc
• The Effect of Mixing on the Observed Metallicity of the Smith Cloud
• Gas Accretion and Star Formation Rates
• Diverse metallicities of Fermi bubble clouds indicate dual origins in the disk and halo
• Caught in the Act: A Metal-Rich High-Velocity Cloud in the Inner Galaxy
• On the Origin of High-velocity Clouds in the Galaxy
• A Component of the Smith High Velocity Cloud Now Crossing the Galactic Plane
• The Long Tails of the Pegasus-Pisces Arch Intermediate Velocity Cloud
• The effect of saturated thermal conduction on clouds in a hot plasma
• The Observed O VI is Just the Tip of the Iceberg: Estimating the Hidden Material in Circumgalactic and Intergalactic Clouds