Astrophysics (Index)About

effective radius

(Re, half-light radius)
(radius of a galaxy within which 1/2 the light is emitted)

Effective radius (aka half-light 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.


(galaxies,measure)
Further reading:
http://en.wikipedia.org/wiki/Effective_radius
https://astronomy.swin.edu.au/cosmos/h/Half-light+Radius

Referenced by pages:
fundamental plane
Kormendy Relation

Index