AbstractThe Polar Large Telescope (PLT) project is primarily aimed at undertaking large, wide band synoptic astronomical surveys in the infrared in order to provide critical data to the forthcoming generation of observational facilities such as ALMA, JWST, LSST and the E–ELT, and to complement the observations obtained with them. Sensitive thermal IR surveys beyond 2.3 μm cannot be carried out from any existing ground based observatory and the Antarctic Plateau is the only place on the ground where it can be envisaged, thanks to its unique atmospheric and environmental properties, such as the turbulence profile (image quality), the low opacity and the reduced thermal background emission of the sky. These unique conditions enable high angular resolution wide field surveys in the near thermal infrared (2.3–5 μm). This spectral range is particularly well suited to tackling key astrophysical questions such as: i) investigating the nature of the distant universe, the first generation of stars and the latest stages of stellar evolution, ii) understanding transient phenomena such as gamma ray-bursts and Type Ia supernovae, iii) increasing our knowledge of extra-solar planets. Further instruments may broaden the expected science outcomes of such a 2–4 m class telescope especially for the characterization of galaxies at very large distance to provide new clues in the mysteries of dark matter and energy. Efforts will be made to merge this project with other comparable projects within an international consortium.

The Antarctic plateau offers exceptional atmospheric and environmental conditions for astronomical observations over a wide range of wavelengths and uniquely favorable to infrared astronomy. Exceptional low sky brightness throughout the near- and mid-infrared and a telescope facility complying with the highest possible dynamic range for photometry, angular resolution and the widefield leads to the possibility of a modest-sized 2m off-axis telescope achieving comparable sensitivity to that of a larger ground-based 8-10m class telescope or a same sized space-based ones.