Astronomy Colloquium - Nia Imara

All stars are observed to form in molecular clouds (MCs). Thousands of these “stellar nurseries” exist in the Milky Way and other galaxies, and given that they set the stage for star formation and influence galactic evolution, astronomers would like to understand how they form and evolve. In this presentation, I will give an overview of the properties of these structures and discuss how astronomers use observations and theory to understand their properties.  I will discuss potential signposts of MC evolution, including CO observations indicating that clouds have large-scale velocity gradients, far-infrared observations of MCs with unusual properties, and 21-cm observations of the atomic gas associated with MCs.