A galaxy rotation curve is a plot of the rotation speed as a function of the
A) galaxy's luminosity.
B) mass of the dark matter halo.
C) brightness of the luminous matter in the galaxy.
D) radius from the center.

Question

Quizplus · Accepted Answer

A galaxy rotation curve shows the relationship between the rotation speed and distance from the center of a galaxy. This curve is typically used to infer the distribution of mass within the galaxy. The mass of the dark matter halo is the dominant factor in determining this distribution, so the rotation curve is a function of radius from the center rather than other parameters like luminosity or brightness.

A Galaxy Rotation Curve Is a Plot of the Rotation