Peculiar (colliding) Galaxies and Active Galaxies Colliding galaxies  tidal distortions, star formation, evolution Active galaxies  bright nuclei (Seyfert)‏ Quasar discovery - the, high redshift surprise “Non-thermal” radiation (synchrotron +)‏ Models: supermassive black hole + accretion Beyond the nucleus – radio galaxies & jets

Galaxies in collision/interacting/mergers Computer simulation – interacting pair The “Antennae”

M51 – the Whirlpool and companion

Ring of active star formation Evidence for mergers Distant Galaxies (large lookback times) – forming via mergers Ring of active star formation

Sgr dwarf elliptical merging with Milky Way

Seyfert galaxies – spirals with very luminous central nucleus strong infrared and radio sources Strong emission H, He, N, O Doppler broadened lines Carl Seyfert

3C 273 spectrum Martin Schmidt 7x1044 ergs/s !

Seyfert galaxies are characterized by extremely bright nuclei, and spectra which have very bright emission lines of hydrogen, helium, nitrogen, and oxygen. These emission lines exhibit strong Doppler broadening, which implies velocities from 500 to 4000 km/s, and are believed to originate near an accretion disk surrounding the central black hole.[3] These emission lines may come from the surface of the accretion disk itself, or may come from clouds of gas illuminated by the central engine in an ionization cone. The exact geometry of the emitting region is difficult to determine due to poor resolution. However, each part of the accretion disk has a different velocity relative to our line of sight, and the faster the gas is rotating around the black hole, the broader the line will be. Similarly, an illuminated disc wind also has a position-dependent velocity.

Quasars – Quasi-stellar Object (QSOs)‏ Central source so luminous appears star-like Radio/Optical/UV/Xray/Gamma-ray radiation

Giant elliptical M87 Cen A – radio emission M87 – jet from nucleus

Active Galaxies Strong radio sources Radio galaxies -- jets of non- thermal radiation – two-lobed appearance due ejection at high energies

The central engine for active galaxies, radio galaxies, quasars -- supermassive black holes 109 x mass Sun Our galactic center 106 x mass Sun http://www.mpe.mpg.de/ir/GC/index.php

VLBI