1999ApJ...525..318P

We compare the statistical properties of J=1⟶0 ¹³CO spectra observed in the Perseus molecular cloud with synthetic J=1⟶0 ¹³CO spectra, computed solving the non-LTE radiative transfer problem for a model cloud obtained as solutions of the three-dimensional magnetohydrodynamic (MHD) equations. The model cloud is a randomly forced super-Alfvénic and highly supersonic turbulent isothermal flow. The purpose of the present work is to test if idealized turbulent flows, without self-gravity, stellar radiation, stellar outflows, or any other effect of star formation, are inconsistent or not with statistical properties of star-forming molecular clouds. We present several statistical results that demonstrate remarkable similarity between real data and the synthetic cloud. Statistical properties of molecular clouds like Perseus are appropriately described by random supersonic and super-Alfvénic MHD flows. Although the description of gravity and stellar radiation are essential to understand the formation of single protostars and the effects of star formation in the cloud dynamics, the overall description of the cloud and of the initial conditions for star formation can apparently be provided on intermediate scales without accounting for gravity, stellar radiation, and a detailed modeling of stellar outflows. We also show that the relation between equivalent line width and integrated antenna temperature indicates the presence of a relatively strong magnetic field in the core B1, in agreement with Zeeman splitting measurements.