Dissecting the Red Sequence - III. Mass-to-Light Variations in 3D Fundamental Plane Space

Understand

The Fundamental Plane has finite thickness and is tilted from the virial relation, indicating that dynamical mass-to-light ratios (Mdyn/L) vary among early type galaxies.

• We use a sample of 16,000 quiescent galaxies from the Sloan Digital Sky Survey to map out variations in Mdyn/L through the 3D Fundamental Plane space defined by velocity dispersion (sigma), effective radius (R_e), and effective surface brightness.
• We consider contributions to Mdyn/L variation due to stellar population effects, IMF variations, and variations in the dark matter fraction within one R_e.
• Along the FP, we find that the stellar population contribution scales as M*/L ~ f(sigma), while the dark matter and/or IMF contribution scales as Mdyn/M* ~ g(Mdyn).