EPoS Contribution
EPoS Contribution
The Star Formation Rate of Molecular Clouds

Paolo Padoan
ICCUB/ICREA, Barcelona, ES
We compute the star formation rate (SFR) in molecular clouds (MCs) that originate ab initio in a new, higher-resolution simulation of supernova-driven turbulence. Because of the large number of well-resolved clouds with self-consistent boundary and initial conditions, we obtain a large range of cloud physical parameters with realistic statistical distributions, an unprecedented sample of star-forming regions to test SFR models and to interpret observational surveys. We confirm the dependence of the SFR per free-fall time, SFRff, on the virial parameter, αvir, found in previous simulations, and compare a revised version of our turbulent fragmentation model with the numerical results. The dependences on Mach number, gas to magnetic pressure ratio and compressive to solenoidal power ratio at fixed αvir are not well constrained, because of random scatter due to time and cloud-to-cloud variations in SFRff. We find that SFRff in MCs can take any value in the range 0-0.2, and its probability distribution peaks at a value SFRff~0.025, consistent with observations. The values of SFRff and the scatter in the SFRffvir relation are consistent with recent measurements in nearby MCs and in clouds near the Galactic center.
Caption: SFR per free-fall time vs. virial parameter for a subset of the clouds selected from the simulation and harboring more than 100 sink particles (filled circles). The model prediction for each cloud is also shown (empty squared symbols). The dashed line is the analytical fit of our revised model using the mean physical parameters averaged over all clouds. The deviations from the model predictions are on average less than 50%
Collaborators:
T. Haugbolle, UC, DK
A. Nordlund, UC, DK
Key publication

Suggested Session: Star formation "laws" and IMF