WEAVE-QSO: A Massive Intergalactic Medium Survey for the William
  Herschel Telescope
  In these proceedings we describe the WEAVE-QSO survey, which will observe
around 400,000 high redshift quasars starting in 2018. This survey is part of a
broader WEAVE survey to be conducted at the 4.2m William Herschel Telescope. We
will focus on chiefly on the science goals, but will also briefly summarise the
target selection methods anticipated and the expected survey plan.
  Understanding the apparent acceleration in the expansion of the Universe is
one of the key scientific challenges of our time. Many experiments have been
proposed to study this expansion, using a variety of techniques. Here we
describe a survey that can measure this acceleration and therefore help
elucidate the nature of dark energy: a survey of the Lyman-alpha forest (and
quasar absorption in general) in spectra towards z>2 quasars (QSOs). Further
constraints on neutrino masses and warm dark matter are also anticipated. The
same data will also shed light on galaxy formation via study of the properties
of inflowing/outflowing gas associated with nearby galaxies and in a cosmic web
context. Gas properties are sensitive to density, temperature, UV radiation,
metallicity and abundance pattern, and so constraint galaxy formation in a
variety of ways. WEAVE-QSO will study absorbers with a dynamic range spanning
more than 8 orders of magnitude in column density, their thermal broadening,
and a host of elements and ionization species. A core principal of the
WEAVE-QSO survey is the targeting of QSOs with near 100% efficiency principally
through use of the J-PAS (r < 23.2) and Gaia (r < 20) data.
