The Large Area Radio Galaxy Evolution Spectroscopic Survey (LARGESS):
  Survey design, data catalogue and GAMA/WiggleZ spectroscopy
  We present the Large Area Radio Galaxy Evolution Spectroscopic Survey
(LARGESS), a spectroscopic catalogue of radio sources designed to include the
full range of radio AGN populations out to redshift z = 0.8. The catalogue
covers roughly 800 square degrees of sky, and provides optical identifications
for 19,179 radio sources from the 1.4 GHz Faint Images of the Radio Sky at
Twenty-cm (FIRST) survey down to an optical magnitude limit of i_mod < 20.5 in
Sloan Digital Sky Survey (SDSS) images. Both galaxies and point-like objects
are included, and no colour cuts are applied. In collaboration with the WiggleZ
and Galaxy And Mass Assembly (GAMA) spectroscopic survey teams, we have
obtained new spectra for over 5,000 objects in the LARGESS sample. Combining
these new spectra with data from earlier surveys provides spectroscopic data
for 12,329 radio sources in the survey area, of which 10,856 have reliable
redshifts. 85% of the LARGESS spectroscopic sample are radio AGN (median
redshift z = 0.44), and 15% are nearby star-forming galaxies (median z = 0.08).
Low-excitation radio galaxies (LERGs) comprise the majority (83%) of LARGESS
radio AGN at z < 0.8, with 12% being high-excitation radio galaxies (HERGs) and
5% radio-loud QSOs. Unlike the more homogeneous LERG and QSO sub-populations,
HERGs are a heterogeneous class of objects with relatively blue optical colours
and a wide dispersion in mid-infrared colours. This is consistent with a
picture in which most HERGs are hosted by galaxies with recent or ongoing star
formation as well as a classical accretion disk.
