ASTRON 1F03 Lecture Notes - Lecture 24: Supermassive Black Hole, Seyfert Galaxy, Synchrotron Radiation
18 Dec 2015
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Document Summary
Some galaxies have active galactic nuclei (agn) extremely bright, blue light sources at their centre. Closest quasar is 1 billion ly away. Once thought to be an odd form of a star, the quasar is a center of violent activity in the hearts of large galaxies. Low-luminosity cousins are seyfert galaxies and radio galaxies. Still: luminosity of the agn can equal that of the rest of the galaxy. Light received ranges from radio to gamma rays. Gas swirling about centers at thousands to tens of thousands of kilometers per second. Must be about the size of our solar system as well as due to rapid variability. Unified model: a central supermassive black hole with an accretion disk. A dense ring (torus) of dust blocks the center. What we see depends on the viewing angle. Supermassive = masses of thousands to tens of billions of solar masses. Jets of material shoot out from the poles of the system.
