Shape of the galactic orbits in the CNOC1 clusters

Citation
Ac. Ramirez et al., Shape of the galactic orbits in the CNOC1 clusters, ASTROPHYS J, 533(1), 2000, pp. 62-72
Citations number
49
Categorie Soggetti
Space Sciences
Journal title
ASTROPHYSICAL JOURNAL
ISSN journal
0004637X → ACNP
Volume
533
Issue
1
Year of publication
2000
Part
1
Pages
62 - 72
Database
ISI
SICI code
0004-637X(20000410)533:1<62:SOTGOI>2.0.ZU;2-O
Abstract
We present an analysis of the orbital properties of nine intermediate-redsh ift clusters of the Canadian Network for Observational Cosmology (CNOCl) su rvey and compare them to a control sample of 12 nearby clusters. Similar to the nearby elliptical galaxies, the bulge-dominated galaxies in clusters a t redshifts similar to 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 cl usters. The strongest orbital segregation is found when galaxies are separa ted by colors [red galaxies with colors in the rest frame (U-V)(0) > 1.4, b lue galaxies with (U-V)(0) less than or equal to 1.4]. Therefore, the segre gation we find seems to modify the star formation activity more efficiently than the internal shape of the galaxies. When we compare the orbits of ear ly-type galaxies at intermediate redshift with those for z = 0, they seem t o develop significant changes, becoming much more eccentric. A different be havior is observed in the late-type galaxies, which present no significant evolution in their orbit shapes.