THE PdBI ARCSECOND WHIRLPOOL SURVEY (PAWS): ENVIRONMENTAL DEPENDENCE OF GIANT MOLECULAR CLOUD PROPERTIES IN M51

Using data from the PdBI Arcsecond Whirlpool Survey (PAWS), we have generated the largest extragalactic giant molecular cloud (GMC) catalog to date, containing 1507 individual objects. GMCs in the inner M51 disk account for only 54% of the total super(12)CO(1-0) luminosity of the survey, but on aver...

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Bibliographic Details
Published in:The Astrophysical journal 2014-03, Vol.784 (1), p.1-32
Main Authors: Colombo, Dario, Hughes, Annie, Schinnerer, Eva, Meidt, Sharon E, Leroy, Adam K, Pety, Jerome, Dobbs, Clare L, Garcia-Burillo, Santiago, Dumas, Gaelle, Thompson, Todd A, Schuster, Karl F, Kramer, Carsten
Format: Article
Language:English
Subjects:
Astrophysics
ASTROPHYSICS, COSMOLOGY AND ASTRONOMY
CORRELATIONS
COSMIC GASES
Disks
DISPERSIONS
EMISSION
EVOLUTION
FEEDBACK
Galactic Astrophysics
Galactic structure
GALAXIES
LUMINOSITY
MASS
MASS DISTRIBUTION
Molecular clouds
MOLECULES
Physical properties
Physics
Sciences of the Universe
STARS
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Summary:Using data from the PdBI Arcsecond Whirlpool Survey (PAWS), we have generated the largest extragalactic giant molecular cloud (GMC) catalog to date, containing 1507 individual objects. GMCs in the inner M51 disk account for only 54% of the total super(12)CO(1-0) luminosity of the survey, but on average they exhibit physical properties similar to Galactic GMCs. We do not find a strong correlation between the GMC size and velocity dispersion, and a simple virial analysis suggests that ~30% of GMCs in M51 are unbound. We have analyzed the GMC properties within seven dynamically motivated galactic environments, finding that GMCs in the spiral arms and in the central region are brighter and have higher velocity dispersions than inter-arm clouds. Globally, the GMC mass distribution does not follow a simple power-law shape. Instead, we find that the shape of the mass distribution varies with galactic environment: the distribution is steeper in inter-arm region than in the spiral arms, and exhibits a sharp truncation at high masses for the nuclear bar region. We propose that the observed environmental variations in the GMC properties and mass distributions are a consequence of the combined action of large-scale dynamical processes and feedback from high-mass star formation. We describe some challenges of using existing GMC identification techniques for decomposing the super(12)CO(1-0) emission in molecule-rich environments, such as M51's inner disk.
ISSN:0004-637X
1538-4357
DOI:10.1088/0004-637X/784/1/3