The Dependence of Prestellar Core Mass Distributions on the Structure of the Parental Cloud

Abstract

The mass distribution of prestellar cores is obtained for clouds with arbitrary internal mass distributions using a selection criterion based on the thermal and turbulent Jeans mass and applied hierarchically from small to large scales. We have checked this methodology comparing our results for a lognormal density PDF with the theoretical CMF derived by Hennebelle and Chabrier, namely a power-law at large scales and a log-normal cutoff at low scales, but our method can be applied to any mass distributions representing a star-forming cloud. This methodology enables us to connect the parental cloud structure with the mass distribution of the cores and their spatial distribution, providing an efficient tool for investigating the physical properties of the molecular clouds that give rise to the prestellar core distributions observed. Simulated fBm clouds with the Hurst exponent close to the value H=1/3 give the best agreement with the theoretical CMF derived by Hennebelle and Chabrier and Chabrier's system IMF. Likewise, the spatial distribution of the cores derived from our methodology show a surface density of companions compatible with those observed in Trapezium and Ophiucus star-forming regions. This method also allows us to analyze the properties of the mass distribution of cores for different realizations. We found that the variations in the number of cores formed in different realizations of fBm clouds (with the same Hurst exponent) are much larger than the expected root N statistical fluctuations, increasing with H.