Recent observational constraints restrict the strict applicability of stellar dynamics in spirals to a few rotation periods. However, stellar dynamics concepts such as periodic orbits are invaluable for understanding the various dynamical processes occurring during much more periods. A distinction of two instability types in stellar systems is pointed out, the first one being well illustrated b...

Accurate and radially extended stellar kinematic data reaching R = 97 from the center are presented for the cD galaxy of Fornax, NGC 1399. The stellar rotation is small (≤ 30 km/s); the stellar velocity dispersion remains constant at 250-270 km/s. The deviations from Gaussian line of sight velocity distributions are small, at the percent level. We construct dynamical models of the galaxy, depro...

We analyze the distribution of stars of arbitrary mass function g(m) around a massive black hole (MBH). Unless g is strongly dominated by light stars, the steady-state distribution function approaches a power-law in specific energy x ≡ −E/mσ2 < xmax with index p = m/4M0, where E is the energy, σ the typical velocity dispersion of unbound stars, and M0 the mass averaged over mgx p max. For light...