1	Astr 5460 Mon., Oct. 4, 2004 This week: Galaxy Interactions Tides Simulations Warps Dynamical Friction Shells (Ch. 7, Combes et al., parts) Unless noted, all figs and eqs from Combes et al or Longair.
2	Galactic Tides
3	Galactic Tides
4	Galactic Tides Tidal forces experienced by an object of diameter d in gravitational interaction with galaxy mass M a distance D away: F_tide ~ GMd/D³ (differentiating Newton) (Why not exactly equal?) Therefore tidal forces very sensitive to D
5	Galactic Tides The text goes into some detail about an analytical approach under a number of simplifying assumptions (p. 183-186). I’m not going to go through it in class, but do look at it. It is similar to some items in Chapter 6 we skipped. The real way to do this anyway is through numeric simulation.
6	Galactic Tides M51 and simulation (Toomre & Toomre 1972)
7	Galactic Tides Antennae Galaxies: http://www.cita.utoronto.ca/~dubinski/antennae/antennae.html
8	Galactic Tides Gas and simulation in text (TT72).
9	Galactic Tides Simulation of “The Mice” in text. Redone more recently by Barnes.
10	Galactic Simulations Joshua Barnes: http://www.ifa.hawaii.edu/faculty/barnes/transform.html John Dubinksi: http://www.cita.utoronto.ca/~dubinski/nbody/ Chris Mihos: http://burro.astr.cwru.edu/models/models.html Bob Berrington (yes, our Bob): http://physics.uwyo.edu/~rberring/ There are others…
11	For Next Time More on interactions, distortions, and dynamical friction. Chapter 8 in Combes et al. on radio sources. Continue on Data Reduction and Analysis New problem set, old homework returned.