Revealing velocity dispersion as the best indicator of a galaxy's color, compared to stellar mass, surface mass density or morphology

TL;DR

This study finds that stellar velocity dispersion is the most effective indicator of a galaxy's color, outperforming stellar mass, surface density, and morphology, suggesting a link to dark matter halo and black hole feedback.

Contribution

It demonstrates that velocity dispersion correlates more strongly with galaxy color than other structural parameters, highlighting its importance in galaxy evolution studies.

Findings

Velocity dispersion shows the strongest residual correlation with galaxy color.

Stellar mass is the weakest predictor of galaxy color among the parameters tested.

Results support a connection between galaxy color, dark matter halo, and black hole feedback.

Abstract

Using data of nearby galaxies from the Sloan Digital Sky Survey we investigate whether stellar mass, central velocity dispersion, surface mass density, or the Sersic n parameter is best correlated with a galaxy's rest-frame color. Specifically, we determine how the mean color of galaxies varies with one parameter when another is fixed. When the stellar mass is fixed we see that strong trends remain with all other parameters, whereas residual trends are weaker when surface mass density, n, or velocity dispersion are fixed. Overall velocity dispersion is the best indicator of a galaxy's typical color, showing the largest residual color dependence when any of the other three parameters are fixed, and stellar mass is the poorest. Other studies have indicated that both the halo and black hole properties are better correlated with velocity dispersion than with stellar mass, surface mass density or Sersic n. Therefore, our results are consistent with a picture where a galaxy's star formation history and present star formation rate are determined to some significant degree by the current properties and assembly history of its dark matter halo and/or the feedback from its central super massive black hole.