THE BLAST SURVEY OF THE VELA MOLECULAR CLOUD: DYNAMICAL PROPERTIES OF THE DENSE CORES IN VELA-D

The Vela-D region, according to the nomenclature given by Murphy & May, of the star-forming complex known as the Vela molecular ridge (VMR), has recently been analyzed in detail by Olmi, who studied the physical properties of 141 pre- and proto-stellar cold dust cores, detected by the Balloon-borne Large-Aperture Submillimeter Telescope (BLAST) during a much larger (55 deg 2 ) Galactic plane survey encompassing the whole VMR. This survey's primary goal was to identify the coldest dense dust cores possibly associated with the earliest phases of star formation. In this work, the dynamical state of the Vela-D cores is analyzed. Comparison to dynamical masses of a sub-sample of the Vela-D cores estimated from the 13 CO survey of Elia is complicated by the fact that the 13 CO linewidths are likely to trace the lower density intercore material, in addition to the dense gas associated with the compact cores observed by BLAST. In fact, the total internal pressure of these cores, if estimated using the 13 CO linewidths, appears to be higher than the cloud ambient pressure. If this were the case, then self-gravity and surface pressure would be insufficient to bind these cores and an additional source of external confinement (e.g., magnetic field pressure) would be required. However, if one attempts to scale down the 13 CO linewidths, according to the observations of high-density tracers in a small sample of sources, then most proto-stellar cores would be effectively gravitationally bound.