Astronomy and Astrophysics, volume 299, 869-884 (1995/7-3)
Dust emission from star forming regions. IV. A survey of IR-strong cloud cores.
MOONEY T., SIEVERS A., MEZGER P.G., SOLOMON P.M., KREYSA E., HASLAM C.G.T. and LEMKE R.
Abstract (from CDS):
As part of an ongoing program "Dust emission from star forming regions" on the cloud core regions of a subset of 51 IR-strong (IRS) and 27 IR-quiet (IRQ) giant molecular clouds (GMCs) defined by CO have been selected for their associated CS and IRAS FIR emission. The dust emission from 13 IRS and 4 IRQ GMCs was mapped with the 15 m SEST telescope at λ1300µm. Two of the GMCs of each category were not detected. A total of 12 regions with dust emission were subsequently mapped with the IRAM 30m telescope at the same wavelength but with an angular resolution of ∼12". Here we present results for six of the dust emission regions. They consist of compact cloud cores embedded in a more extended dust envelope with hydrogen column densities NH>1023/cm-2. The hydrogen mass associated with the dust emission from compact cores and extendeded envelopes accounts for only a few percent of the virial mass derived for the parental GMC. The mass associated with the compact cores on the average accounts for ∼40% of the mass of cores and envelope. The physical parameters of the dust cores are derived and compared with those of W49A, W51A, Orion A and SgrB2 - GMCs well-known for their highly varying high-mass star formation activities per unit mass of molecular hydrogen. The cloud cores of our sample are found to span a similar range. The IR luminosities are estimated from the IRAS survey. The parental IRS GMCs have IR luminosity-to-mass ratios of ∼3-4L☉/M☉. IRQ GMCs have ratios of ≲0.5L☉/M☉.
stars: formation - ISM: clouds, dust, HII regions - infrared: ISM: continuum - radio continuum: ISM