  We study spherically symmetric equilibrium configurations of self-gravitating
massless thermal radiation in asymptotically anti-de Sitter space. In d=4, it
was shown by Page and Phillips that there is a maximum red-shifted temperature,
maximum mass and maximum entropy. For higher central densities, the
temperature, mass and entropy undergo an infinite series of damped
oscillations, corresponding to unstable configurations. We extend this work to
all dimensions $d\geq 3$. We find that in $4\leq d\leq 10$, the behaviour is
similar to the d=4 case. In $d\geq 11$, the temperature, mass and entropy are
monotonic functions of the central density, asymptoting to their maxima as the
central density goes to infinity. In d=3, an exact solution is given by a slice
of the AdS C-metric.
