Computer simulations using implicit Lagrangian hydrodynamics in 3D

The method known as Smoothed Particle Hydrodynamics (SPH) is an important tool in modern numerical Astrophysics. It has been extensively used to simulate a large number of systems ranging from planets to clusters of galaxies. Nevertheless current applications of the method are restricted to dynamical situations because of the limitations in the time-step imposed by the Courant condition. Here we describe the main features of a new implicit SPH code which is able to handle with several thousand particles and, therefore, it can be used to simulate slowly evolving systems.Peer Reviewe