The PdBI arcsecond whirlpool survey (PAWS): Environmental dependence of giant molecular cloud properties in M51
- Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany)
- National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States)
- Institut de Radioastronomie Millimétrique, 300 Rue de la Piscine, F-38406 Saint Martin d'Hères (France)
- School of Physics and Astronomy, University of Exeter, Stocker Road, Exeter EX4 4QL (United Kingdom)
- Observatorio Astronómico Nacional - OAN, Observatorio de Madrid Alfonso XII, 3, E-28014 Madrid (Spain)
- Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States)
- Instituto Radioastronomía Milimétrica, Av. Divina Pastora 7, Nucleo Central, E-18012 Granada (Spain)
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 {sup 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 {sup 12}CO(1-0) emission in molecule-rich environments, such as M51's inner disk.
- OSTI ID:
- 22351538
- Journal Information:
- Astrophysical Journal, Vol. 784, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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