  We recommend a conceptual design study for a spectroscopic facility in the
southern hemisphere comprising a large diameter telescope, fiber system, and
spectrographs collectively optimized for massively-multiplexed spectroscopy. As
a baseline, we propose an 11.4-meter aperture, optical spectroscopic survey
telescope with a five square degree field of view. Using current technologies,
the facility could be equipped with 15,000 robotically-controlled fibers
feeding spectrographs over 360<lambda<1330 nm with options for fiber-fed
spectrographs at high resolution and a panoramic IFU at a separate focus. This
would enable transformational progress via its ability to access a larger
fraction of objects from Gaia, LSST, Euclid, and WFIRST than any currently
funded or planned spectroscopic facility. An ESO-sponsored study
(arXiv:1701.01976) discussed the scientific potential in ambitious new
spectroscopic surveys in Galactic astronomy, extragalactic astronomy, and
cosmology. The US community should establish links with European and other
international communities to plan for such a powerful facility and maximize the
potential of large aperture multi-object spectroscopy given the considerable
investment in deep imaging surveys.
