Speaker
Paul Clark
(ZAH/ITA, University of Heidelberg)
Description
To date, numerical studies of the IMF have adopted initial conditions that are very dense -- often comparable to the densities of individual prestellar cores that are observed in giant molecular clouds (GMCs). These calculations, which start in the regime where the gas and dust are already strongly coupled, can say nothing about conditions we observe in nearby star-forming regions. In addition, the characteristic mass of the IMF in these simulations is strongly biased by their initial conditions. We will present a new suite of models that capture the formation of prestellar cores in GMCs, examining the sensitivity of the characteristic core mass to the environmental conditions in the cloud, such as the strength of the interstellar radiation field (ISRF), the cosmic-ray ionisation rate, and the cloud's metallicity. These are the first calculations to self-consistently capture the transition between the line-cooling and dust cooing regime that has been proposed by Larson (2005) to set the mean Jeans mass for the fragmentation process. We will also discuss the relationship between the mass of the prestellar core, and the final mass of the young star, and where these new models fit into the ""isolated v competitive accretion"" debate. Finally, we will show how the observational properties of the cores, such as their column density and dust temperature profiles, vary as a function of the both the core's environment and its dynamical state (i.e. bound/prestellar v unbound/transient).
Author
Paul Clark
(ZAH/ITA, University of Heidelberg)