Bird’s eye view of molecular clouds in the Milky Way. I. Column density and star formation from sub-parsec to kiloparsec scales

Vol. 653
6. Interstellar and circumstellar matter

Bird’s eye view of molecular clouds in the Milky Way. I. Column density and star formation from sub-parsec to kiloparsec scales

Spilker and collaborators present an attempt to bridge the gap between Galactic and extragalactic observations of molecular cloud structure and star formation. For this, they have compiled a census of molecular clouds within 2 kpc of the Sun, and they have determined the dust-based column density probability distribution (N-PDFs) of the clouds and their relation to star formation. Using these data, the authors have examined their survey region from the outside by using apertures of varying sizes, and they have described how the N-PDFs and their relation to star formation change with size scale. They conclude that the relations between cloud structure and star formation are environment specific and best captured by relative quantities, such as the density contrast. They also conclude that the density structures of individual clouds give rise to a kiloparsec-scale Kennicutt-Schmidt relationship as a combination of sampling effects and blending of different galactic environment!