  Asymptotically Anti-de Sitter Kerr black holes (we focus here on the
five-dimensional case) are associated holographically with matter at conformal
infinity which has a non-zero angular momentum density. It is natural to
attempt to associate this angular momentum with the recently discovered
vorticity of the plasmas produced in peripheral heavy-ion collisions. We assume
that an AdS$_5$-Kerr black hole with angular momentum to mass ratio
$\mathcal{A}$ is dual to boundary matter with an angular momentum density to
energy density ratio also equal to $\mathcal{A}$. With this assumption, we find
that, for collisions corresponding to a given value of $\mathcal{A}$, there is
a maximal possible angular velocity (well below the maximal value permitted by
causality) for such matter at infinity, and that this value is in approximate
agreement with the experimentally reported value of the average plasma
vorticity produced in typical peripheral collisions of heavy ions.
