THE SUPER-ALFVENIC MODEL OF MOLECULAR CLOUDS: PREDICTIONS FOR ZEEMAN SPLITTING MEASUREMENTS

We present synthetic OH Zeeman splitting measurements of a super-Alfvenic molecular cloud model. We select dense cores from synthetic (13)CO maps computed from the largest simulation to date of supersonic and super-Alfvenic turbulence. The synthetic Zeeman splitting measurements in the cores yield a relation between the magnetic field strength, B, and the column density, N, in good agreement with the observations. The large scatter in B at a fixed value of N is partly due to intrinsic variations in the magnetic field strength from core to core. We also compute the relative mass-to-flux ratio between the center of the cores and their envelopes, R(mu), and show that super-Alfvenic turbulence produces a significant scatter also in R(mu), including negative values (field reversal between core center and envelope). We find R(mu) < 1 for 70% of the cores, and R(mu) < 0 for 12%. Of the cores with vertical bar B(LOS)vertical bar > 10 mu G, 81% have R(mu) < 1. These predictions of the super-Alfvenic model are in stark contrast to the ambipolar drift model of core formation, where only R(mu) > 1 is allowed.