TEST-BED SIMULATIONS OF COLLISIONLESS SELF-GRAVITATING SYSTEMS USING THE SCHRODINGER METHOD

The Schrodinger method is a novel approach for modeling numerically se lf-gravitating, collisionless systems that may have certain advantages over N-body and phase-space methods. In particular, smoothing is part of the dynamics and not just the force calculation This paper describ es test-bed simulations which illustrate the viability of the Schrodin ger method, We develop the techniques necessary to handle ''hot'' syst ems as well as spherically symmetric systems, a number of experiments are performed and direct comparisons are made to results obtained usin g a simple shell code. We demonstrate that the method can adequately m odel a stable, equilibrium star cluster by constructing and then evolv ing a Plummer sphere, We also follow the evolution of a system from no nequilibrium initial conditions as it attempts to reach a state of vir ial equilibrium, Finally, we make a few remarks concerning the dynamic s of axions and other bosonic dark matter candidates. The Schrodinger method, in principle, provides an exact treatment of these fields. How ever, such ''scalar field'' simulations are feasible and warranted onl y if the de Broglie wavelength of the particle is comparable to the si ze of the system of interest, a situation that is almost certainly not the case for axions in the Galaxy. The dynamics of axions is therefor e no different from that of any other system of collisionless particle s, We challenge recent claims in the literature that axions in the Gal axy form soliton stars.