We have performed numerical simulations to investigate whether galactic tides can elevate the apparent mass-to-light ratio (script M sign/L) in a dwarf spheroidal galaxy (dSph). In our simulations the dSph is composed only of luminous matter and falls towards the Milky Way on various orbits and in various galactic potentials starting from apogalacticon. We assume a single perigalacticon passage in which the close encounter with the Milky Way produces strong tides that greatly affect the structure and the kinematics of the dSph. We find that even when tides affect the structure and the kinematics of the dSph, they fail to inflate the central script M sign/L. Tides produce large ordered motions rather than large random motions; a clear signature of these motions is apparent rotation. Tides can inflate the global script M sign/L to a value as large as ∼40; however, this is solely due to the ordered motions. Comparing our results with real dSphs, we conclude that galactic tides at the most recent pericenter passage have not inflated the apparent script M sign/L's.
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science