4.6 M and L of AGN Flashcards
What is the shortest variability of an AGN?
1 hour from observational evidence
What is the typical size of an AGN, and how is calculated?
A few au
R_AGN < v t where v is c at most, and t is 1 hour
What is the concept that sets the upper limit for AGN size
Causality as there must be a casual connection between AGN regions due to variability
Define the Eddington Luminosity
The maximum luminosity that an object bound by gravity can have to be stable against radiation pressure
How is the Eddington limit calculated?
Balance radiation force to gravitational force
What is the equation for radiation force?
Momentum flux = flux / c multiplied by the Thomson cross section = 6.65E-29 m^2
What does the Eddington Luminosity allow us to deduce about AGNs?
They are SMBH powered by accretion
What is accretion?
Infalling of material onto an object
What are accretion disks?
The forming of material disks due to initial angular momentum
What causes collisions and shocks within an accretion disk?
The gas converting its potential energy into kinetic energy
What is the Schwarzchild radius?
The radius of a black hole
How efficient are black holes at converting energy?
50% of the rest mass can be converted into KE and radiated away
U = 1/2mc^2 when substituting the Swarzchild radius into the R in PE
