1207.5535 (Rachel L. Ward et al.)

Connecting the Dots: Analyzing Synthetic Observations of Star-Forming Clumps in Molecular Clouds    [PDF]

Rachel L. Ward, James Wadsley, Alison Sills, Nicolas Petitclerc

In this paper, we investigate the extent to which observations of molecular clouds can correctly identify and measure star-forming clumps. We produced a synthetic column density map and a synthetic spectral-line data cube from the simulated collapse of a 5000 M$_{\odot}$ molecular cloud. By correlating the clumps found in the simulation to those found in the synthetic observations, clump masses derived from spectral-line data cubes were found to be quite close to the true physical properties of the clumps. We also find that the `observed' clump mass function derived from the column density map is shifted by a factor of ~ 3 higher than the true clump mass function, due to projection of low-density material along the line of sight. Alves et al. (2007) first proposed that a shift of a clump mass function to higher masses by a factor of 3 can be attributed to a star formation efficiency of 30 %. Our results indicate that this finding may instead be due to an overestimate of clump masses determined from column density observations.

View original: http://arxiv.org/abs/1207.5535