Resumen

We construct a simple accretion model of a rotating pressureless gas sphere onto a Schwarzschild black hole. Far away from the hole, the flow is assumed to rotate as a rigid body. We show how to build analytic solutions in terms of Jacobi elliptic functions. This construction represents a general relativistic generalization of the Newtonian accretion model first proposed by Ulrich (1976). In exactly the same form as it occurs for the Newtonian case, the flow naturally predicts the existence of an equatorial rotating accretion disk about the hole. However, the radius of the disk increases monotonically without limit as the flow reaches the angular momentum corresponding to the maximum limit allowed by the model.