Two families of hot stellar systems, named `ordinary' and {\it 'bright'\/}, are identified in the (log R_e, mu_e) plane built with a luminosity--limited sample of ellipticals and bulges of S0s and spirals of the Virgo and Fornax clusters. This finding, based on ad hoc new observations, is confirmed by a much larger set of literature data for ~1500 galaxies. The `ordinary' family is biparametric: L_T~ I_e R_e^2; its members are fainter that M_B~-19.3 and smaller than re~3 kpc (whatever M_B is). The 'bright' family is uniparametric (mu_e depends on R_e alone) and hosts brightest cluster members and QSO parent galaxies. We show that the segregation in the (log R_e, mu_e) plane has an important counterpart in the behavior of various physical parameters, which is markedly different for galaxies smaller ({`ordinary' family) and larger ('bright' family) than R_e=3 kpc.
The (log re,μe) Plane of Hot Stellar Systems
D'ONOFRIO, MAURO
1993
Abstract
Two families of hot stellar systems, named `ordinary' and {\it 'bright'\/}, are identified in the (log R_e, mu_e) plane built with a luminosity--limited sample of ellipticals and bulges of S0s and spirals of the Virgo and Fornax clusters. This finding, based on ad hoc new observations, is confirmed by a much larger set of literature data for ~1500 galaxies. The `ordinary' family is biparametric: L_T~ I_e R_e^2; its members are fainter that M_B~-19.3 and smaller than re~3 kpc (whatever M_B is). The 'bright' family is uniparametric (mu_e depends on R_e alone) and hosts brightest cluster members and QSO parent galaxies. We show that the segregation in the (log R_e, mu_e) plane has an important counterpart in the behavior of various physical parameters, which is markedly different for galaxies smaller ({`ordinary' family) and larger ('bright' family) than R_e=3 kpc.Pubblicazioni consigliate
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