  The majority of nearby early-type galaxies contains detectable amounts of
emission-line gas at their centers. The emission-line ratios and gas kinematics
potentially form a valuable diagnostic of the nuclear activity and
gravitational potential well. The observed central gas velocity dispersion
often exceeds the stellar velocity dispersion. This could be due to either the
gravitational potential of a black hole or turbulent shocks in the gas. Here we
try to discriminate between these two scenarios.
