Low-Power Radio Sources in the Nuclei of Nearby E/S0 Galaxies: Evidence for Active Nuclei and for Current Star Formation

Extract

Galaxies were selected from the CfA redshift survey (Huchra et al. 1983, Ap.J.Suppl., 52, 189; Tonry 1984, private communication) according to: Decl.(1950) ≥ 0°; photographic or B(0) magnitude ≤ 14 mag; heliocentric velocity ≤ 3000 km s⁻¹; and de Vaucouleurs morphological type T ≤ −1. The third criterion roughly corresponds to a distance limit of 40 Mpc for H₀ = 75 km s⁻¹ Mpc⁻¹. The fourth criterion is equivalent to a Hubble morphological type of elliptical (E) or lenticular (S0), collectively referred to as E/S0 galaxies hereafter. 213 galaxies satisfy the above selection criteria, after 3 Local Group dwarf spheroidals are excluded. Various galaxy catalogs and the recent literature were consulted to check the CfA morphological classifications and to divide the galaxies into Es and S0s. These galaxies comprise a volume– and optical–magnitude–limited sample that is ideally suited to systematic searches in all spectral domains for low-power nuclear activity (Wrobel 1988, A.J., in press).