Environments of Strong / Ultrastrong, Ultraviolet Fe II Emitting Quasars
  We have investigated the strength of ultraviolet Fe II emission from quasars
within the environments of Large Quasar Groups (LQGs) in comparison with
quasars elsewhere, for 1.1 <= <z_LQG> <= 1.7, using the DR7QSO catalogue of the
Sloan Digital Sky Survey. We use the Weymann et al. W2400 equivalent width,
defined between the rest-frame continuum-windows 2240-2255 and 2665-2695 Ang.,
as the measure of the UV Fe II emission. We find a significant shift of the
W2400 distribution to higher values for quasars within LQGs, predominantly for
those LQGs with 1.1 <= <z_LQG> <= 1.5. There is a tentative indication that the
shift to higher values increases with the quasar i magnitude. We find evidence
that within LQGs the ultrastrong emitters with W2400 >= 45 Ang. (more
precisely, ultrastrong-plus with W2400 >= 44 Ang.) have preferred
nearest-neighbour separations of ~ 30-50 Mpc to the adjacent quasar of any
W2400 strength. No such effect is seen for the ultrastrong emitters that are
not in LQGs. The possibilities for increasing the strength of the Fe II
emission appear to be iron abundance, Ly-alpha fluorescence, and
microturbulence, and probably all of these operate. The dense environment of
the LQGs may have led to an increased rate of star formation and an enhanced
abundance of iron in the nuclei of galaxies. Similarly the dense environment
may have led to more active blackholes and increased Ly-alpha fluorescence. The
preferred nearest-neighbour separation for the stronger emitters would appear
to suggest a dynamical component, such as microturbulence. In one particular
LQG, the Huge-LQG (the largest structure known in the early universe), six of
the seven strongest emitters very obviously form three pairings within the
total of 73 members.
