The Star Formation Rate of Molecular Clouds Paolo Padoan ICREA & ICC, University of Barcelona, Barcelona, Spain
The nature of molecular clouds (MCs) and of their fragmentation leading to the birth of stars is still matter of debate. I approach the study of MCs from the point of view of their star formation rate (SFR). Observational estimates of the star formation rate integrated over one free-fall time ($\rm SFR_{\rm ff}$) span a wide range of values, from $\rm SFR_{\rm ff}\sim 0.01$ (Krumholz and Tan 2007) up to $\rm SFR_{\rm ff}\sim 1$ (Murray 2011), suggesting either a strong time dependence of the SFR, or large variations of physical properties from cloud to cloud. In order to address computationally both the time evolution and cloud-to-cloud differences, it is necessary to generate a large number of clouds with realistic distributions of initial and boundary conditions. We pursue this by developing star formation simulations representing large volumes of the ISM, 70 pc and 140 pc at present, and even larger in the near future. To capture the star formation process accurately, our AMR simulations cover an extreme range of scales, down to $\sim 100$~AU in dense cores, which allows us to follow the formation of every individual star and generate a full IMF with tens of thousands of objects. I will present the selection of MC catalogs from the simulations, and discuss their properties in relation to both recent observations and theoretical models. I will focus on the analysis of the $\rm SFR_{\rm ff}$, to understand the origin of its large variations and to test the applicability of theoretical models.
Collaborators: {\AA}ke Nordlund, NBI, Denmark Troels Augboelle, STARPLAN, Denmark	Key publication