2000A&A...353..211H

We studied three members of the sample of 31 cold and luminous southern IRAS sources, which was compiled by Osterloh et al. (1997ApJS..110...71O). These young stellar objects are characterized by extremely red IRAS colours [S_ν(100µm)>S_ν(60µm)>S_ν(25µm)>20xS_ν(12µm)]. Based on their strong CO line wings found in previous observations, the three objects IRAS 12091-6129, IRAS 12405-6238, and IRAS 16019-4903 were selected in order to investigate their nature and the outflow structure in more detail. The mapping in the CO J = 2->1 line as well as the λ1.3 mm continuum dust emission show that all three sources are deeply embedded in dense cloud cores. Strong CO line wings and their mapping indicate the presence of bipolar gas outflows in all three cases. N- and Q-band imaging resolve some substructures inside the λ1.3 mm maps and give evidence for deeply embedded young stellar objects which seem to drive the observed outflows. The comparison of the FIR imaging with the results in K imply that most of the K-band nebulosities are reprocessed radiation escaping through inhomogeneities in a dense cloud. We derived physical parameters such as H₂ column densities and cloud core masses from the CO and the bolometer measurements, and we compared the properties of the outflows and of the surrounding clouds with those found for well-known high-, intermediate- and low-mass objects. This comparison showed that the newly detected outflow systems belong to the most energetic outflows in our galaxy observed so far.