Satellite Disruption

   As the satellite spirals into the center of the primary galaxy tidal forces strip the less gravitationally bound particles in the outer parts of the satellite off. This effect becomes stronger as the two galaxies get closer to each other. In some cases the forces are so strong that the entire satellite galaxy gets ripped apart before reaching the center of the primary. Shown below is the results from one such simulation. Click here for similiar plots for the rest of the simulations.

    The black line in both the upper and lower plots show the separation between the centers of the two galaxies. In the top plot the colored lines show the radii which contain 1/8, 2/8, ... of the total mass of the primary galaxy and the bottom graph shows similiar results for the satellite galaxy. The dip around time=290 is an unfortunate calculation error. Stripping of the outer 5/8s of the satellite mass is visible in the lower plot as an increase in the radii containing half its mass at time=250.

   In all but the six cases with the densest satellites, the satellite becomes entirely disrupted. This is independent of the initial orbital parameters. These cases are unable to produce counter rotating cores since the satellite never reaches the center of the primary. This makes the production of counter rotating cores that much tougher since only a few percent of mergers would have the required density differences between the two galaxies.