Astronomy and Astrophysics
Based on Paper I of this series (Mehlert et al. 2000), we derive central values and logarithmic gradients for the Hβ, Mg and Fe indices of 35 early-type galaxies in the Coma cluster. We find that pure elliptical galaxies have on average slightly higher velocity dispersions, lower Hβ, and higher metallic line-strengths than galaxies with disks (S0). The latter form two families, one comparable to the ellipticals and a second one with significantly higher Hβ, and weaker metallic lines. Our measured logarithmic gradients within the effective radius are ⟨△Mg b⟩ ≈ −0.037, ⟨△⟨Fe⟩⟩ ≈ −0.029, ⟨△Hβ⟩ ≈ +0.017 and ⟨△σ⟩ ≈ −0.063. The gradients strongly correlate with the gradients of σ, but only weakly with the central index values and galaxy velocity dispersion.
Mehlert, D.; Thomas, D.; Saglia, R. P.; and Bender, R., "Spatially Resolved Spectroscopy of Coma Cluster Early-Type Galaxies - III. The Stellar Population Gradients" (2003). Open Dartmouth: Faculty Open Access Articles. 535.