Chaos and elliptical galaxies

Chaos and the Shapes of Elliptical Galaxies

Hubble Space Telescope (HST) observations reveal that the density of stars in most elliptical galaxies rises toward the center in a power-law cusp. Many of these galaxies also contain central dark objects, possibly supermassive black holes. The gravitational force from a steep cusp or black hole will destroy most of the box orbits that constitute the " backbone " of a triaxial stellar system. D...

Elliptical Galaxies

Gravitational Lensing and Elliptical Galaxies

The probability that high-redshift quasars are gravitationally-lensed by intervening galaxies increases rapidly with the cosmological constant, ΩΛ0 (whilst being only weakly dependent on the density parameter, Ωm0), and the low number of lenses observed implies that ΩΛ0 ∼< 0.7 (e.g. Kochanek 1996). One of many uncertainties has been the (small) core radii of elliptical galaxies, which, at least...

Modes of Elliptical Galaxies

Long lived modes of elliptical galaxies can existà la van Kampen. Specific systems may possess long lived oscillations which Landau damp on time scales longer than a Hubble time. Some physical processes such as a close encounter, tidal forces from a cluster or an orbiting satellite could preferentially excite a coherent mode. These may relate to the observed faint structure in elliptical galaxi...

Dynamics of elliptical galaxies.

Elliptical galaxies were once thought to be similar in their structure and dynamics to rotationally flattened bodies like stars. The discovery that elliptical galaxies rotate much more slowly than a fluid body with the same shape has led to a qualitative change in our understanding of the dynamics of these systems. It is now believed that elliptical galaxies are fully triaxial in shape. Self-co...