First, because galaxy formation
theory predicts strongest feedback effects at the high end of
the galaxy luminosity function,
we focused on the most luminous quasars. Second, we concentrated on so-called obscured
quasars in which dusty gas close
to the quasar blocks the lineof-sight to the observer, which
enables us to observe extended
emission line regions without
the overwhelming glare of the
quasar itself. Such objects are
not easy to find in magnitudelimited astronomical surveys;
due to the obscuration, they appear faint at optical wavelengths.
Additionally, they have only been found in
large numbers over the past decade or so.
Gemini Observations
The sample of obscured quasars ݔ