W10 L2 - Galaxies - Black holes and quasars Flashcards
What are the 3 ways that galaxies form
1) primordial collapse, 2) hierarchical clustering, 3) secular evolution
What is the area where light is trapped in perpetual orbit around a black hole?
The photon sphere
What mass is the black hole at the centre of the Milky Way?
About 4 million solar masses
What area is the black hole at the centre of the Milky Way?
Less than the solar system
Which telescope just imaged the black hole at the centre of the Milky Way?
The Event Horizon Telescope
What diameter is the black hole at the centre of the Milky Way?
17 x the Sun, or 1.3 light minutes
What diameter is the black hole at the centre of M87
1.5 light days
What mass is the M87 black hole?
6.5 billion solar masses
What is a quasar?
A type of Active Galactic Nucleus (AGN)
What powers AGNs?
Accretion of gas onto a supermassive black hole
How does energy get emitted from a black hole?
Friction in the accretion disk produces radiation
What range proportion of mass in the accretion disk gets converted to energy and radiated?
10-40%
How is matter ejected from a black hole?
Rotating disc funnels plasma and twisted magnetic fields to poles of black hole
