Is Surface Density of Starlight Synonymous with Surface Brightness?

[Zaphodx57x]

I have a problem that asks for the surface density of starlight at 8 kpc for a particular spiral galaxy.

I have all the information to calculate surface brightness. Does "surface density of starlight" mean "surface brightness", or are these completely different things?

 

[chroot]

I've never heard the term "surface density of starlight." It probably means number of photons per unit area, or flux per unit area.

- Warren