The role of galactic dynamics in shaping the physical properties of giant molecular clouds in Milky Way-like galaxies

• Verfasst von: Jeffreson, Sarah [VerfasserIn]
• Verfasst von: Kruijssen, Diederik [VerfasserIn]
• Verfasst von: Keller, Benjamin W. [VerfasserIn]
• Verfasst von: Chevance, Mélanie [VerfasserIn]
• Verfasst von: Glover, Simon [VerfasserIn]
• Titel: The role of galactic dynamics in shaping the physical properties of giant molecular clouds in Milky Way-like galaxies
• Verf.angabe: Sarah M.R. Jeffreson, J.M. Diederik Kruijssen, Benjamin W. Keller, Melanie Chevance and Simon C.O. Glover
• E-Jahr: 2020
• Jahr: 24 July 2020
• Umfang: 45 S.
• Fussnoten: Gesehen am 07.12.2020
• Titel Quelle: Enthalten in: Royal Astronomical SocietyMonthly notices of the Royal Astronomical Society
• Ort Quelle: Oxford : Oxford Univ. Press, 1827
• Jahr Quelle: 2020
• Band/Heft Quelle: 498(2020), 1, Seite 385-429
• ISSN Quelle: 1365-2966
• DOI: doi:10.1093/mnras/staa2127
• Datenträger: Online-Ressource
• Sprache: eng
• Sach-SW: evolutionary sequences
• Sach-SW: galaxies: evolution
• Sach-SW: galaxies: ISM
• Sach-SW: galaxies: star formation
• Sach-SW: gravitational-instability
• Sach-SW: interstellar-medium
• Sach-SW: ISM: clouds
• Sach-SW: ISM: evolution
• Sach-SW: ISM: kinematics and dynamics
• Sach-SW: magnetic-fields
• Sach-SW: radiative opacities
• Sach-SW: silcc project
• Sach-SW: star-formation rates
• Sach-SW: stellar winds
• Sach-SW: supernova feedback
• Sach-SW: uncertainty principle
• K10plus-PPN: 1742199151

Abstract

We examine the role of the large-scale galactic-dynamical environment in setting the properties of giant molecular clouds in Milky Way-like galaxies. We perform three high-resolution simulations of Milky Way-like discs with the moving-mesh hydrodynamics code AREPO, yielding a statistical sample of similar to 80 000 giant molecular clouds and similar to 55 000 HI clouds. We account for the self-gravity of the gas, momentum, and thermal energy injection from supernovae and HII regions, mass injection from stellar winds, and the non-equilibrium chemistry of hydrogen, carbon, and oxygen. By varying the external gravitational potential, we probe galactic-dynamical environments spanning an order of magnitude in the orbital angular velocity, gravitational stability, midplane pressure, and the gradient of the galactic rotation curve. The simulated molecular clouds are highly overdense (similar to 100x) and overpressured (similar to 25x) relative to the ambient interstellar medium. Their gravoturbulent and star-forming properties are decoupled from the dynamics of the galactic mid-plane, so that the kpc-scale star formation rate surface density is related only to the number of molecular clouds per unit area of the galactic mid-plane. Despite this, the clouds display clear, statistically significant correlations of their rotational properties with the rates of galactic shearing and gravitational free-fall. We find that galactic rotation and gravitational instability can influence their elongation, angular momenta, and tangential velocity dispersions. The lower pressures and densities of the HI clouds allow for a greater range of significant dynamical correlations, mirroring the rotational properties of the molecular clouds, while also displaying a coupling of their gravitational and turbulent properties to the galactic-dynamical environment.