A scaling relation for the molecular cloud lifetime in Milky Way-like galaxies.

Autor: Jeffreson SMR; Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstraße 12-14, D-69120 Heidelberg, Germany., Keller BW; Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstraße 12-14, D-69120 Heidelberg, Germany., Winter AJ; Institut für Theoretische Astrophysik, Zentrum für Astronomie der Universität Heidelberg, Albert-Ueberle-Str. 2, D-69120 Heidelberg, Germany., Chevance M; Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstraße 12-14, D-69120 Heidelberg, Germany., Kruijssen JMD; Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstraße 12-14, D-69120 Heidelberg, Germany., Krumholz MR; Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611 Australia., Fujimoto Y; Earth and Planets Laboratory, Carnegie Institution for Science, 5241 Broad Branch Road, NW, Washington, DC 20015, USA.
Jazyk: angličtina
Zdroj: Monthly notices of the Royal Astronomical Society [Mon Not R Astron Soc] 2021 May 07; Vol. 505 (2), pp. 1678-1698. Date of Electronic Publication: 2021 May 07 (Print Publication: 2021).
DOI: 10.1093/mnras/stab1293
Abstrakt: We study the time evolution of molecular clouds across three Milky Way-like isolated disc galaxy simulations at a temporal resolution of 1 Myr and at a range of spatial resolutions spanning two orders of magnitude in spatial scale from ∼10 pc up to ∼1 kpc. The cloud evolution networks generated at the highest spatial resolution contain a cumulative total of ∼80 000 separate molecular clouds in different galactic-dynamical environments. We find that clouds undergo mergers at a rate proportional to the crossing time between their centroids, but that their physical properties are largely insensitive to these interactions. Below the gas-disc scale height, the cloud lifetime τ life obeys a scaling relation of the form τ life ∝ℓ -0.3 with the cloud size ℓ, consistent with over-densities that collapse, form stars, and are dispersed by stellar feedback. Above the disc scale height, these self-gravitating regions are no longer resolved, so the scaling relation flattens to a constant value of ∼13 Myr, consistent with the turbulent crossing time of the gas disc, as observed in nearby disc galaxies.
(© 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society.)
Databáze: MEDLINE
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