THE NEXT GENERATION CFHT

The 3.6m Canada-France-Hawaii telescope (CFHT) saw rst light in 1979. Since that time, it has proven to be one of the world’s most versatile astronomical research facilities, enabling its users to make fundamental contributions to a remarkably wide range of scientic topics, including the properties of the outer solar system; exoplanet surveys; AGNs, quasars and supermassive black holes; high-redshift supernovae; the chronology of halo formation; stellar structure, evolution and abundances; galaxy evolution; structure formation; the nature of dark matter and dark energy; and the history of cosmic star formation. We briey review the essential features of the CFHT site, telescope and partnership that have made it such a successful research facility for more than 30 years, and critically evaluate its future in the coming decades. The conclusion is that CFHT | which is facing increasingly sti competition from newer, larger, telescopes | will be unable to maintain its position as a forefront facility unless the partners embark upon a bold plan to upgrade to its performance and capabilities. We propose that the present CFHT be upgraded by 2020 to a 10m telescope (installed on the existing pier) equipped with a wide-eld, highly multi-plexed spectrograph (i.e., a FOV 1:5 deg 2 and Nspec 3200 bers). This \next generation" CFHT would allow astronomers from the partnership to take a leadership role in addressing two key scientic questions of the coming decade | the measurement of the equation of state of the universe and the reconstruction of the formation history of the Milky Way. At the same time, it would provide a powerful research tool that would serve a wide user base, allow the partners to leverage observations from JWST, ALMA, LSST, WFIRST, GAIA, TMT and E-ELT, and, potentially, to gain access to other, complementary facilities. Subject headings: telescopes { instrumentation { techniques