Paper detail

Dependence of the ratio of total to visible mass on observable properties of SDSS MaNGA galaxies

Using spectroscopic observations from the SDSS MaNGA DR15, we study the relationships between the ratio of total to visible mass and various parameters characterizing the evolution and environment of the galaxies in this survey. Measuring the rotation curve with the relative velocities of the H-alpha emission line across the galaxy's surface, we estimate each galaxy's total mass. We develop a statistical model to describe the observed distribution in the ratio of total to visible mass, from which we extract a galaxy's most probable value for this mass ratio. We present the relationships between the ratio of total to visible mass and several characteristics describing galactic evolution, such as luminosity, gas-phase metallicity, distance to the nearest neighbor, and position on the color-magnitude diagram. We find that faint galaxies with low metallicities, typically in the blue cloud, have the highest ratios of total to visible mass. Those galaxies that exhibit the second highest ratios of total to visible mass are the brightest with high metallicities, typically members of the red sequence or green valley. AGN activity is likely both the quenching mechanism and the feedback that drives the mass ratio higher in these massive galaxies. Finally, we introduce a parametrization that predicts a galaxy's ratio of total to visible mass based on its photometry and luminosity.