Updates: 09.05.2012 (Umut)
In star-formation, the protostellar envelope is surrounded by large amounts of cold gas and dust particles which reduces the intensity of the light reflecting from the protostar. Therefore the detection of low-mass protostars in their early phases is hard at optical and infrared wavelength regimes. However, it is very common to observe such cold objects at the longer wavelengths such as submillimeter and millimeter wavelengths. With the evolution of the protostellar phase from molecular cloud to protoplanetary disks, the observation wavelengths are also evolves from mm to IR. A 4m+ class ground based IR telescope can be very useful to follow-up the observations of current and old IR/submm space missions, together with the large surveys.
ALMA (de Graauw et al) is a new state-of-art submm/mm observation facility recently commisioned. The observatory has 66 antennas with a 12 metre size antennas. Many of the sources observed with ALMA can also be followed-up with DAG.
Herschel Space Observatory (Pilbratt et al. 2010) is a cornerstome mission of ESA, a far-IR/submm telescope with a 3.5~metre diameter. It was launched in May 2009 and orbiting at the L2 position of Earth with an estimated lifetime of around 3.5 years.
Other mm/submm telescopes include, James Clerk Maxwell Telescope (JCMT, 15m), IRAS 30m, Atacama Pathfinder Experiment (APEX, 12m), Nobeyama Radiotelescope (40m), Onsala Raditelescope (20m), Caltech Submillimeter Observatory (CSO),
Other mm/submm interferometers include, Submillimeter Array (SMA), extended Submillimeter Array (eSMA), Plateu de Bureau Interferometer (PdBI)