A single distance sample of molecular outflows from high-mass young stellar objects

We have made (CO)-C-12 2-1 and 1-0 maps of eleven molecular outflows associated with intermediate to high-mass young stellar objects (YSOs) in order to establish whether the correlations between out ow parameters and source bolometric luminosity hold in the high-mass regime. It is important to consider the effects of Malmquist-type biases when looking at high-mass YSOs, as they are generally much more distant than their low mass counterparts. We therefore chose only objects located at similar to2 kpc. We find that the relations show much more scatter than is seen in similar studies of low-mass YSOs. We also find that the mass-spectrum is significantly steeper in high-mass outflows, indicating a larger mass-fraction at lower velocities, a low collimation factor (similar to1-2) and no Hubble-like relationship.