Line Strengths in Elliptical Galaxies

Typical metallicity gradients of elliptical galaxies are {delta}[Fe/H]/{delta}log(r){=~}-0.3, which is flatter than the gradients predicted by monolithic collapse simulations. The metallicity gradients do not correlate with any physical properties of galaxies, including central and mean metallicities, central velocity dispersions {sigma}_0_, absolute B magnitudes M_B_, absolute effective radii R_e_, and dynamical masses of galaxies.

By using the metallicity gradients, we have calculated mean stellar metallicities for individual ellipticals. Typical mean stellar metallicities are <[Fe/H]> {=~} -0.3 and range from <[Fe/H]>{=~}-0.8 to +0.3, which is contrary to what Gonzalez & Gorgas (1996) claimed; the mean metallicities of ellipticals are not universal. The mean metallicities correlate well with {sigma}_0{sigma}_ and dynamical masses, though relations for M_B_ and R_e_ include significant scatters.