The breakdown of the galaxy-halo connection

In the standard model of cosmology and galaxy formation, galaxies are intrinsically linked to the dark matter halos in which they form.

Dark matter halos and galaxies grow in mass through gravitational accretion, but the process of turning gas into stars is a complex process that has been shown to decouple the growth of galaxies and halos. It is, however, not clear on what timescales this happens.

This project will study the relationship between halo and galaxy growth in Fourier space using cosmological hydrodynamical simulations, with the goal of identifying the links between galaxies and halos as a function of timescale.

We will answer the question of on what timescales the star-formation and chemical enrichment histories can be considered fully stochastic.

By studying this relationship in different galaxy types and in different simulations, we will link different frequencies to different physical processes.

In parallel, we will construct a simple empirical stochastic model that we will fit to data from the Dark Energy Spectroscopic Instrument survey, with the goal of observationally constraining the timescale at which the growth of halos and galaxies decouple, and comparing to predictions from simulations.