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Oscar Agertz. Profile photo.

Oscar Agertz

Associate Professor / Senior university lecturer / Wallenberg Academy Fellow

Oscar Agertz. Profile photo.

Hot gas accretion fuels star formation faster than cold accretion in high-redshift galaxies

Author

  • Zuzanna Kocjan
  • Corentin Cadiou
  • Oscar Agertz
  • Andrew Pontzen

Summary, in English

We use high-resolution (35pc) hydrodynamical simulations of galaxy formation to investigate the relation between gas accretion and star formation in galaxies hosted by dark matter haloes of mass at. At high-redshift, cold-Accreted gas is expected to be readily available for star formation, while gas accreted in a hot mode is expected to require a longer time to cool down before being able to form stars. Contrary to these expectations, we find that the majority of cold-Accreted gas takes several hundred Myr longer to form stars than hot-Accreted gas after it reaches the inner circumgalactic medium (CGM). Approximately 10 per cent of the cold-Accreted gas flows rapidly through the inner CGM on to the galactic disc. The remaining 90 per cent is trapped in a turbulent accretion region that extends up to per cent of the virial radius, from which it takes several hundred Myr for the gas to be transported to the star-forming disc. In contrast, most hot shock-heated gas avoids this 'slow track', and accretes directly from the CGM on to the disc where stars can form. We find that shock-heating of cold gas after accretion in the inner CGM and supernova-driven outflows contribute to, but do not fully explain, the delay in star formation. These processes combined slow down the delivery of cold-Accreted gas to the galactic disc and consequently limit the rate of star formation in Milky Way mass galaxies at.

Department/s

  • Astrophysics
  • eSSENCE: The e-Science Collaboration

Publishing year

2024-10-01

Language

English

Pages

918-929

Publication/Series

Monthly Notices of the Royal Astronomical Society

Volume

534

Issue

1

Document type

Journal article

Publisher

Oxford University Press

Topic

  • Astronomy, Astrophysics and Cosmology

Keywords

  • accretion, accretion discs
  • galaxies: disc
  • galaxies: formation
  • galaxies: star formation

Status

Published

ISBN/ISSN/Other

  • ISSN: 0035-8711