Cluster and field elliptical galaxies at z ~ 1.3

Abstract

We compared the properties of 56 elliptical galaxies selected from three clusters at 1.2 2x10^{11} Msun) and large (Re > 4-5 kpc) ellipticals with respect to the cluster. Nonetheless, at M*< 2x10^{11} Msun, the two populations are similar. The size-mass relation of cluster and field ellipticals at z~1.3 defines two different regimes, above and below a transition mass m_t~2-3x10^{10} Msun: at lower masses the relation is nearly flat (Re\propto M*^{-0.1\pm0.2}), the mean radius is constant at ~1 kpc and, consequenly, Sigma_Re ~ Sigma_1kpc while, at larger masses, the relation is Re\propto M*^{0.64\pm0.09}. The transition mass marks the mass at which galaxies reach the maximum Sigma_Re. Also the Sigma_1kpc-mass relation follows two different regimes, above and below m_t, (Sigma_1kpc\propto M*^{0.64\ >m_t}_{1.07\