The environments of high redshift radio galaxies and quasars: probes of
  protoclusters
  We use the GALFORM semi-analytical model to study high density regions traced
by radio galaxies and quasars at high redshifts. We explore the impact that
baryonic physics has upon the properties of galaxies in these environments.
Star-forming emission-line galaxies (Ly{\alpha} and H{\alpha} emitters) are
used to probe the environments at high redshifts. Radio galaxies are predicted
to be hosted by more massive haloes than quasars, and this is imprinted on the
amplitude of galaxy overdensities and cross-correlation functions. We find that
Ly{\alpha} radiative transfer and AGN feedback indirectly affect the clustering
on small scales and also the stellar masses, star- formation rates and gas
metallicities of galaxies in dense environments. We also investigate the
relation between protoclusters associated with radio galaxies and quasars, and
their present- day cluster descendants. The progenitors of massive clusters
associated with radio galaxies and quasars allow us to determine an average
protocluster size in a simple way. Overdensities within the protoclusters are
found to correlate with the halo descendant masses. We present scaling
relations that can be applied to observational data. By computing projection
effects due to the wavelength resolution of modern spectrographs and
narrow-band filters we show that the former have enough spectral resolution to
map the structure of protoclusters, whereas the latter can be used to measure
the clustering around radio galaxies and quasars over larger scales to
determine the mass of dark matter haloes hosting them.
