and accretion of new material is a central component of galaxy evolution.

An episode of star formation increases a galaxy’s stellar mass and enriches the ISM. A substantial body of work has shown that there are correlations between stellar mass (${\hbox{$M_{\star}$}}$), star formation rate (SFR), and gas phase oxygen abundance. The correlation between ${\hbox{$M_{\star}$}}$ and gas phase oxygen abundance is called the Mass-Metallicity Relation [MZR; @Lequeux79; @Tremonti04]. The MZR extends from low mass, extremely metal deficient galaxies like Leo P [@Skillman13] up to massive galaxies with 2-3 times the solar oxygen abundance [@Tremonti04; @Moustakas11].

The MZR often serves as a benchmark for models of galaxy evolution because the details of the MZR are direct probes of the underlying physics. For instance, @Tremonti04 describe how the shape of the MZR requires galactic winds to efficiently remove metals from low mass galaxies. Subsequent cosmological models [e.g. @Dave06b; @Oppenheimer06; @Finlator08; @Dave11a; @Dave11b] incorporated winds into their cosmological models in order to better understand the origin of the MZR. In the context of their momentum driven wind models, the mass loading parameter $\eta \equiv \dot{M}_{\rm outflow}/\dot{M}_{\star}$ is proportional to the inverse of the velocity dispersion of the halo, which scales with the halo mass 