Supersonic turbulence in the Perseus molecular cloud

We compare the statistical properties of J = 1 --> 0 (CO)-C-13 spectra obse rved in the Perseus molecular cloud with synthetic J = 1 --> 0 (CO)-C-13 sp ectra, computed solving the non-LTE radiative transfer problem for a model cloud obtained as solutions of the three-dimensional magnetohydrodynamic (M HD) equations. The model cloud is a randomly forced super-Alfvenic and high ly supersonic turbulent isothermal flow. The purpose of the present work is to test if idealized turbulent flows, without self-gravity, stellar radiat ion, stellar outflows, or any other effect of star formation, are inconsist ent or not with statistical properties of star-forming molecular clouds. We present several statistical results that: demonstrate remarkable similarit y between real data and the synthetic cloud. Statistical properties-of mole cular clouds like Perseus are appropriately described by random supersonic and super-Alfvenic MHD flows. Although the description of gravity and stell ar radiation are essential to understand the formation of single protostars and the effects of star formation in the cloud dynamics, the overall descr iption of the cloud and of the initial conditions for star formation can ap parently be provided on intermediate scales without accounting for gravity, stellar radiation, and a detailed modeling of stellar outflows. We also sh ow that the relation between equivalent line width and integrated antenna t emperature indicates the presence of a relatively strong magnetic field in the core B1, in agreement with Zeeman splitting measurements.