Optimization of Moment Masking for CO Spectral Line Surveys

We describe and refine the masked moment method used to suppress noise in Galactic and extragalactic spectral line surveys. By applying the refined technique to an essentially noise-free CO molecular cloud survey with Gaussian noise added, we determine the optimum masking parameters for typical CO surveys such as those presented in Dame et al. (2001, ApJ, 547, 792)