The Magellanic Mopra Assessment (MAGMA). I. The Molecular Cloud
  Population of the Large Magellanic Cloud
  We present the properties of an extensive sample of molecular clouds in the
Large Magellanic Cloud (LMC) mapped at 11 pc resolution in the CO(1-0) line. We
identify clouds as regions of connected CO emission, and find that the
distributions of cloud sizes, fluxes and masses are sensitive to the choice of
decomposition parameters. In all cases, however, the luminosity function of CO
clouds is steeper than dN/dL \propto L^{-2}, suggesting that a substantial
fraction of mass is in low-mass clouds. A correlation between size and
linewidth, while apparent for the largest emission structures, breaks down when
those structures are decomposed into smaller structures. We argue that the
correlation between virial mass and CO luminosity is the result of comparing
two covariant quantities, with the correlation appearing tighter on larger
scales where a size-linewidth relation holds. The virial parameter (the ratio
of a cloud's kinetic to self-gravitational energy) shows a wide range of values
and exhibits no clear trends with the CO luminosity or the likelihood of
hosting young stellar object (YSO) candidates, casting further doubt on the
assumption of virialization for molecular clouds in the LMC. Higher CO
luminosity increases the likelihood of a cloud harboring a YSO candidate, and
more luminous YSOs are more likely to be coincident with detectable CO
emission, confirming the close link between giant molecular clouds and massive
star formation.
