The stellar halo metallicity-luminosity relationship for spiral galaxies

The stellar haloes of spiral galaxies bear important chemodynamical signatures of galaxy formation. We present here the analysis of 89 semi-cosmological spiral galaxy simulations, spanning ~4 mag in total galactic luminosity. These simulations sample a wide variety of merging histories and show significant dispersion in halo metallicity at a given total luminosity – more than a factor of 10 in metallicity. Our preliminary analysis suggests that galaxies with a more extended merging history possess haloes which have younger and more metal-rich stellar populations than the stellar haloes associated with galaxies with a more abbreviated assembly. A correlation between a halo's metallicity and its surface brightness has also been found, reflecting the correlation between halo metallicity and its stellar mass. Our simulations are compared with recent Hubble Space Telescope observations of resolved stellar haloes in nearby spirals.