Modeling dwarf galaxies of the local volume with the semi-analytic model Galacticus

Abstract

Dwarf galaxies are ubiquitous and extremely sensitive to various internal and external feedback forms. Thus, studying dwarfs in various environments is critical for understanding galaxy evolution. The best-studied dwarfs are those of the Local Group (LG). The Local Group (LG) is home to some of the best-studied dwarfs, but thanks to recent surveys like SDSS, PAndAS, and DES, we now know of more than twice as many dwarfs as before. Concurrently, the Milky Way satellites have been successfully modeled with simulations (e.g. MINT Justice League, FIRE II); however, at a high computational cost. In this work, we run the Semi-Analytic Model (SAM) \textsc{Galacticus} on a Milky Way analog. We show, for the first time, with correctly chosen astrophysical prescriptions and parameters, \textsc{Galacticus} can reproduce the $z\,=\,0$ properties and star formation histories of the Milky Way dwarfs, including the ultra-faints, allowing efficient modeling of even the faintest dwarfs with minimal computational cost. Recently, surveys such as SCABS and PISCeS have extended our understanding of dwarf satellite systems beyond the LG, such as the Centaurus A (Cen A) elliptical galaxy, which is located 3.8 Mpc away and has a $M_{vir}$ of $10^{13} M_{\odot}$. By applying the same astrophysical assumptions and parameters used in the Milky Way simulations, we can match the properties of the observed Cen A satellites and reproduce the shape of the Cen A luminosity function at distances beyond 250 kpc. However, our modeled luminosity function cannot replicate the steepening observed at $M_V<-12$ within 200 kpc. This can only be reproduced for higher temperatures of the Inter-Galactic Medium of Cen A system, suggesting it may result from Cen A’s AGN.