  In order to better understand stellar dynamics in merging systems, such as
NGC 6240, we examine the evolution of central stellar velocity dispersion
(\sig) in dissipative galaxy mergers using a suite of binary disk merger
simulations that include feedback from stellar formation and active galactic
nuclei (AGNs). We find that $\sigma_*$ undergoes the same general stages of
evolution that were observed in our previous dissipationless simulations:
coherent oscillation, then phase mixing, followed by dynamical equilibrium. We
also find that measurements of $\sigma_*$ that are based only upon the youngest
stars in simulations consistently yield lower values than measurements based
upon the total stellar population. This finding appears to be consistent with
the so-called "$\sigma_*$ discrepancy," observed in real galaxies. We note that
quasar-level AGN activity is much more likely to occur when $\sigma_*$ is near
its equilibrium value rather than during periods of extreme $\sigma_*$.
Finally, we provide estimates of the scatter inherent in measuring $\sigma_*$
in ongoing mergers.
