New 50-m-class single dish telescope: Large Submillimeter Telescope(LST)

We report on the plan to construct a 50 m class millimeter (mm) and sub-mm single dish telescope, the Large Submillimeter Telescope (LST). The telescope is optimized for wide-area imaging and spectroscopic surveys in the 70 to 420 GHz main frequency range, which just covers main atmospheric windows at millimeter and submillimeter wavelengths for good observing sites such as the ALMA site in Chile. We also target observations at higher frequencies of up to 1 THz, using an inner part high-precision surface. Active surface control is required in order to correct gravitational and thermal deformations of the surface. The LST will facilitate new discovery spaces such as wide-field imaging with both continuum and spectral lines, along with new developments for time domain science. With exploiting synergy with ALMA and other telescopes, LST can contribute to a wide range of topics in astronomy and astrophysics, e.g., astrochemistry, star formation in the Galaxy and galaxies, evolution of galaxy clusters via SZ effect. We also report the recent progress on the technical study, e.g., the tentative study of the surface error budget and challenges to correction for the wind-load effect.