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Effective Radius

(radius of a galaxy within which 1/2 the light is emitted)

Effective Radius is a measure of the size of a Galaxy that accommodates the fact that while galaxies grow thinner (fewer stars, less gas) with distance from the center, they don't have well-defined edges. The effective radius is defined to be the radius within which 1/2 the galaxy's light is emitted.


Referenced by:
Fundamental Plane