Angular Momentum Accretion onto Disc Galaxies

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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.
Original languageEnglish
Title of host publicationAstronomy in Focus - XXX
Subtitle of host publicationProceedings
EditorsM. T. Lago
PublisherCambridge University Press
Pages228-232
Volume30
DOIs
Publication statusPublished - 3-Mar-2020
EventAstronomy in Focus XXX: Volume 14 - Symposium A30 - August 2018 - Viena, Australia
Duration: 20-Aug-201831-Aug-2018

Publication series

NameProceedings of the International Astronomical Union
PublisherInternational Astronomical Union
NumberA30
Volume14
ISSN (Print)1743-9213
ISSN (Electronic)1743-9221

Conference

ConferenceAstronomy in Focus XXX
Country/TerritoryAustralia
CityViena
Period20/08/201831/08/2018

Keywords

  • Angular momentum
  • gas accretion
  • hot halo
  • metallicity gradient
  • corona

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