  Extended gas haloes around galaxies are a ubiquitous prediction of galaxy
formation scenarios. However, the density profiles of this hot halo gas is
virtually unknown, although various profiles have been suggested on theoretical
grounds. In order to quantitatively address the gas profile, we compare
galaxies from direct cosmological simulations with analytical solutions of the
underlying gas equations. We find remarkable agreement between simulations and
theoretical predictions. We present an expression for this gas profile with a
non-trivial dependence on the total mass profile. This expression is useful
when setting up equilibrium galaxy models for numerical experiments.

Astrophysics