Viktor Toth (Budapest) -- Star formation in Planck-detected cold clouds

I present recent results on star-forming clouds, obtained especially in connection with the project Galactic Cold Cores. While most of the galactic interstellar medium and star formation research have been confined to a small number of nearby regions, the all-sky Planck catalogue of Galactic Cold Clumps (PGCC, Planck 2015 results XXVIII 2015) allows an almost unbiased study of the early phases of star-formation in our Galaxy. The Herschel Key Program „Galactic Cold Cores” (PI. M. Juvela) explored about 350 Planck Galactic Cold Clumps, sampling Planck clumps with a broad range of physical parameters and environments. Planck and Herschel data have revealed a clear evolution of dust that is parallel to the star formation process. This is visible as increased dust opacity and opacity spectral index towards the cold clumps. In addition to the Herschel, we have performed NIR and optical observations, cm and mm-line radio follow-ups, and utilized further archival data. We have derived the density and velocity distributions as well as the stages of the associated star formation from gravitationally bound cores to YSOs. The nature of Planck clumps varies from IRDCs to tiny nearby cold clouds. Thus our studies reveal the rich structure of both star forming and starless clouds. Some of the clumps are embedded in large complexes, even close to OB associations, while others are isolated and lay far from UV luminous objects.