MODELING LINE-PROFILES OF PROTOSTELLAR COLLAPSE IN B335 WITH THE MONTE-CARLO METHOD

A collapsing dark cloud core, B335, is modeled as an inside-out collapse. The radiative transfer code uses the Monte Carlo method and new collision rates for CS. Line profiles for several observed transitions of CS and H2CO are computed. We confirm that a double-peaked spectrum with a stronger blue peak is a good qualitative signature of infall. Compared to the models using the large velocity gradient method by Zhou et al., our best-fit model using the Monte Carlo method has 20% smaller infall radius, 70% larger CS abundance, and 30% larger H2CO abundance. Also, infall radii found from CS and H2CO agree better than they did in the modeling by Zhou et al. Our model also produces off-center spectra close to the observations.