Astrophysics and Astronomy Commons^™

Cluster Versus Field Elliptical Galaxies And Clues On Their Formation, Mariangela Bernardi, Alvio Renzini, Luiz N. Da Costa, Gary Wegner

Dartmouth Scholarship

Using new observations for a sample of 931 early-type galaxies, we investigate whether the Mg₂-σ₀ relation shows any dependence on the local environment. The galaxies have been assigned to three different environments depending on the local overdensity (clusters, groups, and field); we used our complete redshift database to guide the assignment of galaxies. It is found that cluster, group, and field early-type galaxies follow almost identical Mg₂-σ₀ relations, with the largest Mg₂ zero-point difference (clusters minus field) being only 0.007±0.002 mag. No correlation of the residuals is found with the morphological type or …