Advanced

Physical properties and scaling relations of molecular clouds : The effect of stellar feedback

Grisdale, Kearn ; Agertz, Oscar LU ; Renaud, Florent LU and Romeo, Alessandro B. (2018) In Monthly Notices of the Royal Astronomical Society 479(3). p.3167-3180
Abstract

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 withMWobservations. GMCscaling 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... (More)

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 withMWobservations. GMCscaling 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.

(Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Galaxies:evolution, Galaxies:formation, Galaxies:ism, Galaxies:structure
in
Monthly Notices of the Royal Astronomical Society
volume
479
issue
3
pages
14 pages
publisher
Oxford University Press
external identifiers
  • scopus:85051557452
ISSN
0035-8711
DOI
10.1093/mnras/sty1595
language
English
LU publication?
yes
id
c6db7be9-e483-40f8-aaff-c74631c994d3
date added to LUP
2018-09-07 08:21:57
date last changed
2020-04-07 04:59:04
@article{c6db7be9-e483-40f8-aaff-c74631c994d3,
  abstract     = {<p>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 withMWobservations. GMCscaling 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∝R<sup>2.3</sup> and σ∝R<sup>0.56</sup>.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.</p>},
  author       = {Grisdale, Kearn and Agertz, Oscar and Renaud, Florent and Romeo, Alessandro B.},
  issn         = {0035-8711},
  language     = {eng},
  month        = {09},
  number       = {3},
  pages        = {3167--3180},
  publisher    = {Oxford University Press},
  series       = {Monthly Notices of the Royal Astronomical Society},
  title        = {Physical properties and scaling relations of molecular clouds : The effect of stellar feedback},
  url          = {http://dx.doi.org/10.1093/mnras/sty1595},
  doi          = {10.1093/mnras/sty1595},
  volume       = {479},
  year         = {2018},
}