Shape of the galactic orbits in the CNOC1 clusters.
RAMIREZ A.C., DE SOUZA R.E. and SCHADE D.
Abstract (from CDS):
We present an analysis of the orbital properties of nine intermediate-redshift clusters of the Canadian Network for Observational Cosmology (CNOC1) survey and compare them to a control sample of 12 nearby clusters. Similar to the nearby elliptical galaxies, the bulge-dominated galaxies in clusters at redshifts ∼0.1-0.4 present orbits that are more eccentric than those of disk-dominated galaxies. However, the orbital segregation is less significant than that found for elliptical and spiral galaxies in nearby clusters. The strongest orbital segregation is found when galaxies are separated by colors [red galaxies with colors in the rest frame (U-V)0>1.4, blue galaxies with (U-V)0≤1.4]. Therefore, the segregation we find seems to modify the star formation activity more efficiently than the internal shape of the galaxies. When we compare the orbits of early-type galaxies at intermediate redshift with those for z=0, they seem to develop significant changes, becoming much more eccentric. A different behavior is observed in the late-type galaxies, which present no significant evolution in their orbit shapes.
Cosmology: Observations - Galaxies: Clusters: General - Galaxies: Evolution - Galaxies: Kinematics and Dynamics - Galaxies: Structure