We present the results of a study that uses numerical simulations to interpret observations of tidally disturbed satellites around the Milky Way. When analysing the simulations from the viewpoint of an observer, we find a break in the slope of the star count and velocity dispersion profiles in our models at the location where unbound stars dominate. We conclude that 'extra-tidal' stars and enhanced velocity dispersions observed in the outskirts of Galactic satellites are caused by contamination by stellar debris from the tidal interaction with the Milky Way. However, a significant bound population can exist beyond the break radius and we argue that it should not be identified with the tidal radius of the satellite. We also develop and test a method for determining the mass-loss rate from a Galactic satellite using its extra-tidal population. We apply this method to observations of globular clusters and dwarf spheroidal satellites of the Milky Way, and conclude that a significant fraction of each of these satellite systems is likely to be destroyed within the next Hubble time. Finally, we demonstrate that this mass-loss estimate allows us to place some limits on the initial mass function (IMF) of stars in a cluster from the radial dependence of its present-day mass function (PDMF).
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science