Strong dependence of the physical properties of cores on spatial resolution in observations and simulations

Vol. 653
6. Interstellar and circumstellar matter

Strong dependence of the physical properties of cores on spatial resolution in observations and simulations

Louvet and collaborators present a systematic study of the effect of spatial resolution on the measured properties, particularly the mass, of dense stellar cores, the smallest gas entities that are currently believed to collapse and form a star, or a multiple star system. The results are chilling. Using both observations and simulations, they find that extracting dense cores from the same molecular cloud at different resolutions (distances) does not produce consistent results. They also find that the mass spectrum of the extracted dense cores is a function of resolution, implying that characterizing the rate of conversion of dense gas into stars is currently out of reach. The authors point out that the much used Gaussian beam deconvolution of imaging data to infer dense core sizes produces highly biased results in this context. The results in this paper have direct consequences on our overall ability to characterize the initial conditions of star formation, providing a warni! ng that it is a more complex task than currently assumed.