The volume densities of giant molecular clouds in M83

被引：13

作者：

Heiner, J. S. ^{[1
,2
]}

Allen, R. J. ^{[2
]}

Wong, O. I. ^{[3
]}

van der Kruit, P. C. ^{[1
]}

机构：

[1] Univ Groningen, Kapteyn Astron Inst, NL-9700 AV Groningen, Netherlands

[2] Space Telescope Sci Inst, Baltimore, MD 21218 USA

[3] Yale Univ, Dept Astron, New Haven, CT 06520 USA

来源：

ASTRONOMY & ASTROPHYSICS | 2008年 / 489卷 / 02期

关键词：

galaxies : individual : M83; galaxies : ISM; ISM : clouds; ISM : molecules; ultraviolet : galaxies; radio lines : galaxies;

D O I：

10.1051/0004-6361:200810430

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

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.

引用

页码：533 / U28

页数：22

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