Description
We examine scaling relations of dispersion-supported galaxies over more than eight orders of magnitude in luminosity by transforming standard fundamental plane parameters into a space of mass, radius, and luminosity. The radius variable r_1/2_ is the deprojected (three-dimensional) half-light radius, the mass variable M_1/2_ is the total gravitating mass within this radius, and L_1/2_ is half the luminosity. We find that from ultra-faint dwarf spheroidals to giant cluster spheroids, dispersion-supported galaxies scatter about a one-dimensional "fundamental curve" through this MRL space.
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