The volume densities of giant molecular clouds in M83

J. S. Heiner*, R. J. Allen, O. I. Wong, P. C. van der Kruit

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

13 Citations (Scopus)
55 Downloads (Pure)

Abstract

Using observed GALEX far-ultraviolet (FUV) fluxes and VLA images of the 21-cm HI column densities, along with estimates of the local dust abundances, we measure the volume densities of a sample of actively star-forming giant molecular clouds (GMCs) in the nearby spiral galaxy M83 on a typical resolution scale of 170 pc.

Our approach is based on an equilibrium model for the cycle of molecular hydrogen formation on dust grains and photodissociation under the influence of the FUV radiation on the cloud surfaces of GMCs.

We find a range of total volume densities on the surface of GMCs in M83, namely 0.1-400 cm(-3) inside R(25), 0.5-50 cm(-3) outside R(25). Our data include a number of GMCs in the HI ring surrounding this galaxy. Finally, we discuss the effects of observational selection, which may bias our results.

Original languageEnglish
Pages (from-to)533–541
Number of pages22
JournalAstronomy & Astrophysics
Volume489
Issue number2
DOIs
Publication statusPublished - Oct-2008

Keywords

  • galaxies : individual : M83
  • galaxies : ISM
  • ISM : clouds
  • ISM : molecules
  • ultraviolet : galaxies
  • radio lines : galaxies
  • LARGE-SCALE DISSOCIATION
  • OPTICAL SPECTROSCOPY
  • NEARBY GALAXIES
  • SPIRAL GALAXIES
  • STAR-FORMATION
  • 1-0 EMISSION
  • HII-REGIONS
  • GAS
  • PHOTODISSOCIATION
  • TELESCOPE

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