Johanna Malinen


Accuracy of core mass estimates in simulated observations of dust emission


M. Juvela, D.C. Collins, T. Lunttila, P. Padoan



We study the reliability of mass estimates obtained for molecular cloud cores using sub-mm and infrared dust emission. We use MHD-simulations and radiative transfer to produce synthetic observations with resolution and noise typical of Herschel surveys. We estimate dust colour temperatures using intensity pairs or all five Herschel wavelengths, calculate column densities and compare estimated and true masses. We study also the influence of embedded sources. The shape, but not the position, of mass spectrum is reliable against observational errors and analysis biases. This changes only if cores have optical depths higher than in basic hydrostatic equilibrium. Observations underestimate beta when there are temperature variations along line of sight. A bias can be observed when true beta varies with wavelength. Internal heating sources produce inverse correlation between colour temperature and beta that may be difficult to separate from any intrinsic beta(T) relation of the dust grains.