  In this article we study a kinetic model which describes the interaction
between a gas and radiation. Specifically, we consider a scaling limit in which
the interaction between the gas and the photons takes place much faster than
the collisions between the gas molecules themselves. We prove in the
homogeneous case that the solutions of the limit problem solve a kinetic
equation for which a well-posedness theory is considered. The proof of the
convergence to a new kinetic equation is obtained analyzing the dynamics of the
gas-photon system near the slow manifold of steady states.
