Semi-analytic galaxy formation models

Taken from Hirschmann+13 and Somerville&Dave 2016

 

Taken from Hirschmann+13 and Somerville&Dave 2016

Semi-analytic galaxy formation models (SAMs) provide a powerful approach to study statistical properties of galaxy and black hole (BH) populations over cosmic time – providing a fully complementary approach to cosmological hydrodynamic simulations. Most state-of-the-art SAMs are built on merger trees of dark-matter halos predicted by cosmological dark-matter-only N-body simulations, which provide the redshift evolution of dark-matter halos and their number densities. To populate individual dark-matter halos with galaxies, matter flows are traced between different baryonic reservoirs (e.g., stellar disk mass, stellar bulge mass, cold gas mass, hot gas mass, BH mass etc.). For that, empirically motivated recipes for baryon-physical processes are adopted – described by sets of differential equations, which can be numerically solved at very low computational costs despite large cosmological volumes. Thanks to the latter advantage, SAMs allow for a fast and comprehensive exploration of the impact of various baryonic-physical models (e.g. star formation, stellar feedback, BH feedback etc.) on the formation and evolution of galaxies, tracing at the same time the large-scale structure in our Universe. 

Specifically, at GalSpec, we are developing and working with the GAlaxy Evolution and Assembly (GAEA) model. GAEA builds on the model published in DeLucia and Blaizot (2007), it has been first introduced in Hirschmann et al. (2016) featuring a full chemical enrichment scheme and novel model for stellar feedback, but many prescriptions have been updated significantly over the past years.  We are currently working on an updated model that includes all the implementations published in our most recent papers (improved recipes for star formation, environmental processes as well as BH growth and feedback). We have also been computing mock light cones of galaxy populations, to provide guidance for the planning and interpretation of near-future missions with the revolutionary EUCLID telescope. Here (https://sites.google.com/inaf.it/gaea/home?authuser=0) you can find more details on and model predictions from GAEA. 

Moreover, at GalSpec, we take advantage of light cones of the SantaCruz SAM (e.g., Somerville+08, Hirschmann+12, Yung+21), which have been constructed for the JWST Early Science Release Program “CEERs”, to enlighten galaxy evolution and BH growth during the epoch of re-ionisation.

Adapted from Mo, Mao and White, 2010