flat rotation curve
xam-e carxeš-e taxt
Fr.: courbe de rotation plate
A galactic → rotation curve in which the → rotation velocity is constant in the outer parts. The flat component is preceded by a rising curve that shows solid body rotation in the very center of the → galaxy. A flat rotation curve implies that the mass is still increasing linearly with radius. See also → dark matter.
Keplerian rotation curve
xam-e carxeš-e Kepleri (#)
Fr.: courbe de rotation keplérienne
A → rotation curve in which the speed of the orbiting body is inversely proportional to the → square root of its distance from the mass concentrated at the center of the system.
Fr.: courbe de rotation
A plot of the variation in → orbital velocity of stars and → interstellar matter with distance from the center of a → galaxy. A "flat" rotation curve indicates that the mass of the galaxy increases linearly with distance from its center. See also: farsi→ Keplerian rotation curve
Rotation; → curve.