Molecular Cloud Properties and Star Formation in Primitive Galaxies

With the advent of ALMA astronomers will be able to routinely use millimeter-wave observations of molecules and dust to study galaxies at cosmological distances. Open questions remain, however, on how CO relates to H_2, and how HI and H_2 relate to star formation activity in local systems. In an ongoing effort to understand how the tracers of molecular gas relate to the total molecular mass and to other properties of galaxies, we will discuss the analysis of resolved molecular cloud properties from combined single-dish and interferometric data in nearby dwarf galaxies -- the closest primitive systems. This analysis shows that, despite a variety of underlying physical conditions, Giant Molecular Clouds have very similar properties from galaxy to galaxy, including the Milky Way. However, we find that CO is not a good tracer of total molecular mass in low metallicity systems. In the Small Magellanic Cloud (SMC), the galaxy with lowest heavy element abundance where CO has been detected, we analyze a combination of Spitzer and IRAS data to obtain a map of H_2 accross the galaxy and compare it to CO. We use this measurement of total molecular mass to place the SMC in star formation rate/molecular mass space, and we find that it falls on the same Schmidt-Law relationship as larger galaxies when only H_2 is considered