What does the M-sigma relation demonstrate about black holes?
A) They result from massive stars' deaths.
B) That black holes and galaxies grow together.
C) They grow primarily through accretion.
D) That black holes form the majority of mass within galactic bulges.

Question

Quizplus · Accepted Answer

The M-sigma relation demonstrates that black holes and galaxies grow together, as there is a correlation between the mass of the central black hole in a galaxy and the velocity dispersion of stars in the galaxy's bulge. This suggests that the growth of the black hole and the galaxy are linked in some way.

Answer: C
 The M-sigma relation also suggests that black holes grow primarily through accretion, as the velocity dispersion of stars in the galactic bulge is a proxy for the mass of the black hole, and accretion is the process by which black holes gain mass.

Note: While A and D are true statements about black holes, they are not specifically demonstrated by the M-sigma relation.

What Does the M-Sigma Relation Demonstrate About Black Holes