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Oscar Agertz. Profile photo.

Oscar Agertz

Assistant Professor / Associate senior university lecturer / Wallenberg Academy Fellow

Oscar Agertz. Profile photo.

Runaway stars masquerading as star formation in galactic outskirts

Author

  • Eric P. Andersson
  • Florent Renaud
  • Oscar Agertz

Summary, in English

In the outskirts of nearby spiral galaxies, star formation is observed in extremely low gas surface densities. Star formation in these regions, where the interstellar medium is dominated by diffuse atomic hydrogen, is difficult to explain with classic star formation theories. In this letter, we introduce runaway stars as an explanation for this observation. Runaway stars, produced by collisional dynamics in young stellar clusters, can travel kiloparsecs during their main-sequence lifetime. Using galactic-scale hydrodynamic simulations including a treatment of individual stars, we demonstrate that this mechanism enables the ejection of young massive stars into environments where the gas is not dense enough to trigger star formation. This results in the appearance of star formation in regions where it ought to be impossible. We conclude that runaway stars are a contributing, if not dominant, factor to the observations of star formation in the outskirts of spiral galaxies.

Department/s

  • Lund Observatory
  • eSSENCE: The e-Science Collaboration

Publishing year

2021

Language

English

Pages

29-34

Publication/Series

Monthly Notices of the Royal Astronomical Society: Letters

Volume

502

Issue

1

Document type

Journal article

Publisher

Oxford University Press

Topic

  • Astronomy, Astrophysics and Cosmology

Keywords

  • galaxies: star formation
  • ISM: evolution
  • stars: kinematics and dynamics

Status

Published

ISBN/ISSN/Other

  • ISSN: 1745-3925