Angular Momentum Accretion onto Disc Galaxies

Abstract

Throughout the Hubble time, gas makes its way from the intergalactic medium into galaxies fuelling their star formation and promoting their growth. One of the key properties of the accreting gas is its angular momentum, which has profound implications for the evolution of, in particular, disc galaxies. Here, we discuss how to infer the angular momentum of the accreting gas using observations of present-day galaxy discs. We first summarize evidence for ongoing inside-out growth of star forming discs. We then focus on the chemistry of the discs and show how the observed metallicity gradients can be explained if gas accretes onto a disc rotating with a velocity 20-30% lower than the local circular speed. We also show that these gradients are incompatible with accretion occurring at the edge of the discs and flowing radially inward. Finally, we investigate gas accretion from a hot corona with a cosmological angular momentum distribution and describe how simple models of rotating coronae guarantee the inside-out growth of disc galaxies.

5 pages, 2 figures, proceeding of FM6 "Galactic Angular Momentum", XXX IAU General Assembly, Vienna 2018

References in corpus (31)

• Star Formation in the Milky Way and Nearby Galaxies
• A Highly Consistent Framework for the Evolution of the Star-Forming "Main Sequence" from z~0-6
• The Circumgalactic Medium
• Virial shocks in galactic haloes?
• Giant Gamma-ray Bubbles from Fermi-LAT: AGN Activity or Bipolar Galactic Wind?
• Galaxies in a simulated $\Lambda$CDM Universe I: cold mode and hot cores
• Chemical evolution with radial mixing
• Gaseous Galaxy Halos
• COLD GASS, an IRAM Legacy Survey of Molecular Gas in Massive Galaxies: II. The non-universality of the Molecular Gas Depletion Timescale
• Constraining the Milky Way's Hot Gas Halo with OVII and OVII Emission Lines
• Specific SFR profiles in nearby spiral galaxies: quantifying the inside-out formation of disks
• The Direct Detection of Cool, Metal-Enriched Gas Accretion onto Galaxies at z ~ 0.5
• On the origin of the galaxy luminosity function
• A Reservoir of Ionized Gas in the Galactic Halo to Sustain Star Formation in the Milky Way
• Efficiency of gas cooling and accretion at the disc-corona interface
• Angular Momentum and Galaxy Formation Revisited: Effects of Variable Mass-to-light Ratios
• The Detection of Inside-out Disk Growth in M33
• Supernova-driven gas accretion in the Milky Way
• The ACS Nearby Galaxy Survey Treasury V. Radial Star Formation History of NGC 300
• Gas Accretion via Condensation and Fountains
• Coming of Age in the Dark Sector: How Dark Matter Haloes grow their Gravitational Potential Wells
• The Rotation of the Hot Gas Around the Milky Way
• The origin of the high-velocity cloud complex C
• Accretion, radial flows and abundance gradients in spiral galaxies
• On the Metallicity and Origin of the Smith High-Velocity Cloud
• Estimating gas accretion in disc galaxies using the Kennicutt-Schmidt law
• Radial Flows and Angular Momentum Conservation in Galactic Chemical Evolution
• Ionized absorbers as evidence for supernova-driven cooling of the lower Galactic corona
• Timing the evolution of quiescent and star-forming local galaxies
• The angular momentum of cosmological coronae and the inside-out growth of spiral galaxies
• Radial Star Formation Histories in Fifteen Nearby Galaxies