Luminosity Density

Luminosity Density
Let j be the luminosity per unit column of a spherical distribution. The the observed distribution is
(1) ...

If one assumes that the variation of mass density with radius is known for a galaxy - for instance, by equating the mass density to some fixed multiple (the mass-to-light ratio) of the luminosity density, ...

We can also compute the luminosity density of the sampled region: N*L/V = N*

For an untruncated King model, the luminosity density r(r) follows the simple form One frequently introduces a tidal truncation energy (radius) to remedy the infinite-luminosity problem, but then the intensity distribution becomes non-analytic.

See also: Density, Mass, Luminosity, Distance, Light