The impact of galactic properties and environment on the quenching of central and satellite galaxies: A comparison between SDSS, Illustris and L-Galaxies

TL;DR

This study analyzes how galactic and environmental factors influence star formation quenching in central and satellite galaxies, comparing observational data from SDSS with predictions from Illustris and L-Galaxies simulations.

Contribution

It introduces a new statistical method to isolate the impact of individual parameters on galaxy quenching and compares observational results with simulation predictions.

Findings

Central velocity dispersion is the strongest predictor of quenching.

Simulations qualitatively match the trend for centrals but differ in quenching efficiency.

Environmental effects are significant for satellite quenching, especially local density.

Abstract

We quantify the impact that a variety of galactic and environmental properties have on the quenching of star formation. We collate a sample of $\sim$ 400,000 central and $\sim$ 100,000 satellite galaxies from the Sloan Digital Sky Survey Data Release 7 (SDSS DR7). Specifically, we consider central velocity dispersion ($\sigma_{c}$), stellar, halo, bulge and disk mass, local density, bulge-to-total ratio, group-centric distance and galaxy-halo mass ratio. We develop and apply a new statistical technique to quantify the impact on the quenched fraction ($f_{\rm Quench}$) of varying one parameter, while keeping the remaining parameters fixed. For centrals, we find that the $f_{\rm Quench} - \sigma_{c}$ relationship is tighter and steeper than for any other variable considered. We compare to the Illustris hydrodynamical simulation and the Munich semi-analytic model (L-Galaxies), finding that our results for centrals are qualitatively consistent with their predictions for quenching via radio-mode AGN feedback, hinting at the viability of this process in explaining our observational trends. However, we also find evidence that quenching in L-Galaxies is too efficient and quenching in Illustris is not efficient enough, compared to observations. For satellites, we find strong evidence that environment affects their quenched fraction at fixed central velocity dispersion, particularly at lower masses. At higher masses, satellites behave identically to centrals in their quenching. Of the environmental parameters considered, local density affects the quenched fraction of satellites the most at fixed central velocity dispersion.