The Detailed Science Case for the Maunakea Spectroscopic Explorer, 2019
  edition
  (Abridged) The Maunakea Spectroscopic Explorer (MSE) is an end-to-end science
platform for the design, execution and scientific exploitation of spectroscopic
surveys. It will unveil the composition and dynamics of the faint Universe and
impact nearly every field of astrophysics across all spatial scales, from
individual stars to the largest scale structures in the Universe. Major pillars
in the science program for MSE include (i) the ultimate Gaia follow-up facility
for understanding the chemistry and dynamics of the distant Milky Way,
including the outer disk and faint stellar halo at high spectral resolution
(ii) galaxy formation and evolution at cosmic noon, via the type of
revolutionary surveys that have occurred in the nearby Universe, but now
conducted at the peak of the star formation history of the Universe (iii)
derivation of the mass of the neutrino and insights into inflationary physics
through a cosmological redshift survey that probes a large volume of the
Universe with a high galaxy density. MSE is positioned to become a critical hub
in the emerging international network of front-line astronomical facilities,
with scientific capabilities that naturally complement and extend the
scientific power of Gaia, the Large Synoptic Survey Telescope, the Square
Kilometer Array, Euclid, WFIRST, the 30m telescopes and many more.
