Physical properties and scaling relations of molecular clouds: the effect of stellar feedback
Artikel i vetenskaplig tidskrift, 2018

Using hydrodynamical simulations of entire galactic discs similar to the Milky Way (MW), reaching 4.6{ pc} resolution, we study the origins of observed physical properties of giant molecular clouds (GMCs). We find that efficient stellar feedback is a necessary ingredient in order to develop a realistic interstellar medium, leading to molecular cloud masses, sizes, velocity dispersions, and virial parameters in excellent agreement with MW observations. GMC scaling relations observed in the MW, such as the mass-size (M-R), velocity dispersion-size (σ-R), and the σ-RΣ relations, are reproduced in a feedback-driven ISM when observed in projection, with M∝R2.3 and σ∝R0.56. When analysed in 3D, GMC scaling relations steepen significantly, indicating potential limitations of our understanding of molecular cloud 3D structure from observations. Furthermore, we demonstrate how a GMC population's underlying distribution of virial parameters can strongly influence the scatter in derived scaling relations. Finally, we show that GMCs with nearly identical global properties exist in different evolutionary stages, where a majority of clouds being either gravitationally bound or expanding, but with a significant fraction being compressed by external ISM pressure, at all times.

galaxies:ISM

galaxies:evolution

galaxies:formation

galaxies:structure

Författare

Kearn Grisdale

University of Oxford

University of Surrey

Oscar Agertz

Lunds universitet

Florent Renaud

Lunds universitet

University of Surrey

Alessandro Romeo

Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik, Extragalaktisk astrofysik

Monthly Notices of the Royal Astronomical Society

0035-8711 (ISSN) 1365-2966 (eISSN)

Vol. 479 3 3167-3180

Ämneskategorier

Astronomi, astrofysik och kosmologi

Fundament

Grundläggande vetenskaper

DOI

10.1093/mnras/sty1595

Mer information

Senast uppdaterat

2018-08-29