Gas and dust in submillimeter galaxies and massive disk galaxies at high-redshift (Manuel Aravena, NRAO)

In the course of our MAMBO 1.2 mm survey of the COSMOS field we have found a sample of 25 bright submillimeter galaxiess. Most of these sources appear to fit well within the scenario of IR hyper-luminous, interacting galaxies at typical redshift of ~2, however some of them are rare objects in the transition between a gas-rich starburst to a QSO phase. Others appear to form a significant population of previously unaccounted very high-redshift (z>3) massive galaxies, while some seem to be embedded in substantial overdensities of massive disk galaxies at z~1.5-2.0. In this talk, I will present observations obtained with various (sub)mm telescopes and interferometers that point to this very varied nature of some of the most massive systems in the early Universe. Finally I will show our new detections of large amounts of cold molecular gas in massive disk galaxies at z=1.5 with the Very Large Array (VLA), which indicate low star-formation efficiencies, similar to local spiral galaxies. This population of gas-rich galaxies is 10x more numerous than SMGs, representing ideal targets for future (on-going) surveys with ALMA and EVLA.