Abstract
A set of N-body simulations of disk galaxies has been carried out to study the heating effects on the disk component, resulting from two-body encounters. We have quantified the diffusion coefficients and relaxation times in the radial and vertical directions at a given reference radius. Disk self-heating plays a marginal role in the vertical heating of the disk while it has an important contribution to the radial heating whenever the halo is not poorly sampled; otherwise, both the radial and vertical heating will be dominated by disk-halo particle encounters. Also, it is found that the disk is more efficiently heated in the radial direction than in the vertical one at a given radius. Finally, an expression has been derived to estimate, a priori, the number of halo particles (inside the reference radius) required to maintain the heating of the disc within a desired level.
