Abstract:
We develop a new technique to extract galaxy halo light spectra at large galactocentric radii using the DEIMOS multi-object spectrograph. We use the metallicity sensitive Calcium triplet to obtain reliable metallicity gradients out to unprecedented radii (2.5r_e) in large early type galaxies. The shape and slope of metallicity gradients with galactocentric radius contain information about the formation and evolution of galaxies. Results of a pilot study are presented and compared to theoretical models to constrain the processes involved in the formation and evolution of individual galaxies.