Simulating Turbulence

We investigate the core mass distributio (CMD) resulting from numerical models of turbulent fragmentation of molecular clouds. In particular we study its dependence on the sonic rms Mach numberMs. We analyze simulations withMs ranging from 1 to 15 to show that, asMs increases, the number of cores increases as well, while their average m ss decreases. This stems from the fact that high Mach number flows produce many and strong shocks on intermediate to small spatial scales, leading to a highly fragmented density structure. We also show that the CMD from purely turbulent fragmentation does not follow a single power law, but can be described by a function that changes its shape continuously, probably similar to a lognormal function. The CMD in supersonic turbulent flows does not have a universal slope, which casts some doubt on attempts to directly relate the CMD to a universal initial mass function. Subject headinggs: ISM: clouds — methods: numerical — stars: formation — turbulence Online material: color figure