The Kennicutt-Schmidt relation in the local Milky Way: dependency on scale and age

Andri Spilker

Tuesday, Dec. 6th, 10:35CET

The Kennicutt-Schmidt relation is widely studied in the Milky Way and other galaxies, but it is not clear how the relation depends upon the scale on which it is studied. We present two experiments where we look at star forming clouds in the local Galactic environment at different scales to study this dependency. We first examine a sample of molecular clouds that is as complete as possible within 2 kpc distance, with YSO counts for the majority of them. In this sample we see no KS relation between the clouds, but the relation appears when we mimic observations of the clouds at larger scales. It arises from a combination of sampling effects and blending of different galactic environments. We then use three dimensional data of dust density and young stars within 400 pc distance to study the KS relation in 3D, at different scales and with stars of different ages. We see a trend towards a steeper relation for larger scales and younger stars, and describe this relationship with a simple model. This represents an important step in linking together Galactic and extra-Galactic knowledge on star formation.