Spectroscopic Cosmological Surveys in the Far-IR
  We show the feasibility of spectroscopic cosmological surveys with the SAFARI
instrument onboard of SPICA. The work is done through simulations that make use
of both empirical methods, i.e. the use of observed luminosity functions and
theoretical models for galaxy formation and evolution. The relations assumed
between the line emission to trace AGN and star formation activity have been
derived from the observations of local samples of galaxies. The results
converge to indicate the use of blind spectroscopy with the SAFARI FTS at
various resolutions to study galaxy evolution from the local to the distant
(z~3) Universe. Specifically, two different and independent galaxy evolution
models predict about 7-10 sources to be spectroscopically detected in more than
one line in a 2'x 2'SAFARI field of view, down to the expected flux limits of
SAFARI, with about 20% of sources to be detected at z>2. SPICA-SAFARI will be
therefore excellent at detecting high-z sources and at assessing in a direct
way their nature (e.g whether mainly AGN or Star Formation powered) thanks to
blind spectroscopy.
