The descriptions of debris evolution in this chapter are illustrated with a set of N-body simulationsN-body simulations (see Dehnen & Read 2011, for a review of techniques) of satellite disruption presented in Hendel & Johnston (2015). The self-gravity of the satellite in these simulations was calculated with the Self-Consistent Field (SCF) code, which uses basis function expansions to represent the mutual influence of the particles on each other (Hernquist & Ostriker 1992). In each simulation, a 105 particle NFW-profileNavarro, Frenk, & White (NFW) profile (Navarro et al. 1996) satellite was inserted at the apogalacticon of its orbit in a static, spherical host halo, with characteristics of dark matter halos thought to host Milky-Way-sized galaxies (NFW profile with a virial mass of M = 1.77 × 1012 M⊙ and a scale radius of 24.6 kpc, see Navarro et al. 1996). The satellite was evolved first in isolation, then the host potential was turned on slowly over 10 satellite internal dynamical times to reduce artificial gravitational shocking. Total energy is conserved to better than ∼1% of the satellite internal potential energy during all simulations.
Our figures illustrate the results of simulations for satellites with masses m = 6.5 × 106 M⊙ to m = 6.5 × 108 M⊙ (where m is the mass enclosed within 35 NFW scale radii, the radius out to which particles were realized in the NFW distribution). The scale radius r0 was adjusted for each mass so that their density was the same with a base value of 0.86 kpc for the 6.5× 106 M⊙ satellite. These satellites were allowed to evolve for 8 Gyrs along orbits with the same energy as a circular orbit at R = 25 kpc in the host potential, but with angular momenta between 10% and 90% of that of a circular orbit (i.e. L / Lcirc = 0.1 - 0.9) to contrast evolution on a near-circular to a highly-eccentric orbit.