Quasars
Physics: AQA A Level, topic 9.3.3
Quasars
Quasi-stellar objects (QSOs or Quasars) are bizarre objects discovered with enormous cosmological redshifts.
Bright radio sources
- Quasars were discovered as very bright sources in the radio spectrum.
- When an optical telescope was used to see if there was a visible object at the source of the radio waves, all that was found was what looked like a very faint star.
Extremely bright
- Quasars have very large cosmological redshifts (up to 7!) which means they are very far away indeed.
- To be observed at these distances in both visible and radio telescopes implies that they are very much more luminous than the entire Milky Way.
Supermassive black holes
- It is now believed that quasars are formed from supermassive black holes up to 800 million times more massive than the sun.
- The radiation emitted comes from the gas that rapidly spirals into the black hole.
Test yourself on Quasars
Which of these are true of quasars?