Quenching and Galaxy Demographics

TL;DR

This paper enhances galaxy evolution models by incorporating detailed quenching mechanisms and satellite galaxy effects, providing analytical relations and validating results with SDSS data to improve realistic astrophysical simulations.

Contribution

It introduces an extended set of continuity equations including satellite quenching and time evolution, offering analytical relations that reduce parameter complexity for galaxy demographic modeling.

Findings

Derived analytical relations between quiescent and active galaxy populations.

Validated model against SDSS DR7 galaxy sample.

Provided time-dependent amplitude of the Schechter function.

Abstract

The open-data revolution in astronomy is forcing the community to develop sophisticated analysis methods that heavily rely on realistic simulations. The phenomenology of the evolution of galaxy demographics can be described by a set of continuity equations invoking two quenching mechanisms: mass quenching and satellite quenching. The combination of these two mechanisms produces a double Schechter function for the quiescent population, as is observed in the low-redshift universe. In this paper we consider these quenching mechanisms, explicitly including satellite galaxies, and add the exact time evolution of the star-forming population. These new features complete the current versions of these continuity equations, and are essential for the realistic simulations required in modern extra-galactic astrophysics. We derive the analytical relation between the quiescent and the active populations, reducing considerably the parameter space for the simulation. In addition, we derive the analytical time dependence of the amplitude of the Schechter function. Finally, we validate our results against the SDSS DR7 galaxy sample. The model will be implemented in the SkyPy library and the main plots sonified using STRAUSS.