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1998AJ....116..643L - Astron. J., 116, 643-656 (1998/August-0)
A group-group merger at a redshift of z = 0.84?.
LUBIN L.M., POSTMAN M. and OKE J.B.
Abstract (from CDS):
The morphological analysis of the galaxy populations of Cl 0023+0423 suggests that both groups are largely dominated by spiral galaxies. Early-type fractions are 33% or less. These modest early-type fractions have implications for both cluster formation and group evolution. Studies of open clusters at z = 0.31-0.54 indicate that they have early-type fractions between 45%-80%. If the Cl 0023+0423 system is the predecessor of such a cluster, the comparison may suggest that some fraction of early-type galaxies are formed between redshifts of z ∼ 0.8 and z ∼ 0.3; however, the morphological fractions are still highly uncertain. In addition, the modest early-type fractions in both groups may be inconsistent with the strong correlation between velocity dispersion and early-type fraction observed in nearby groups of galaxies. Both groups apparently have relatively low early-type populations, irrespective of their velocity dispersion. If the groups of Cl 0023+0423 are typical of galaxy groups at high redshift, and if high-redshift groups are the progenitors of local groups, this result may also imply that some early-type formation is occurring at redshifts of z ≲ 0.8. These results do not preclude the formation of early-type galaxies at very high redshift, as many observations suggest; however, the observations of the Cl 0023+0423 system may imply that a fraction of the early-type population is forming and/or undergoing significant evolution at redshifts of z < 1.
Abstract Copyright: ∼
Journal keyword(s): Cosmology: Observations - Galaxies: Clusters: Individual: Alphanumeric: Cl 0023+0423 (read: GHO 002118+040630) - Galaxies: Evolution
CDS comments: MDS 17, 20, 82, 115 = [OPL98] MDS J0023+0423 17, 20, 82, 115. ClG: format 'ClG JHHMM+DDMM' (J missing).
Simbad objects: 10
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