Isotropic AdS/CFT fireball

We study the AdS/CFT thermodynamics of the spatially isotropic counterpart of the Bjorken similarity flow in $d$-dimensional Minkowski space with $d\ge 3$, and of its generalization to linearly expanding $d$-dimensional Friedmann-Robertson-Walker cosmologies with arbitrary values of the spatial curvature parameter $k$. The bulk solution is a nonstatic foliation of the generalized Schwarzschild-AdS black hole with a horizon of constant curvature $k$. The boundary matter is an expanding perfect fluid that satisfies the first law of thermodynamics for all values of the temperature and the spatial curvature, but it admits a description as a scale-invariant fluid in local thermal equilibrium only when the inverse Hawking temperature is negligible compared with the spatial curvature length scale. A Casimir-type term in the holographic energy-momentum tensor is identified from the threshold of black hole formation and is shown to take different forms for $k\ge 0$ and $k<0$.