RADIO-CONTINUUM SOURCES IN NEARBY AND BRIGHT E/S0 GALAXIES - SAMPLE SELECTION AND WELL-STUDIED CASES

A volume-limited sample of 216 nearby (upsilon-Sun less-than-or-equal-to 3000 km s-1) and optically bright (B less-than-or-equal-to 14 mag) E/SO galaxies was drawn from the Center of Astrophysics redshift survey (Huchra et al. 1983; 1984 version). This volume-limited sample is ideally suited to systematic searches in all spectral domains for low power activity in E/SO galaxies. As an aid to those embarking on such studies, the basic optical properties of the sample are tabulated. References to all available radio-continuum data on the 216 galaxies through 1989 August are given in an Appendix. These data show that twelve galaxies are confirmed radio sources for which VLA images are available. A synthesis of the radio properties of these twelve real that (1) all exhibit compact radio cores with powers approximately 10(21-23)W Hz-1 and, usually, structure on parsec scales; (2) kpc-scale structures are common, and are usually collimated and two sided with respect to the compact core; and (3) galactic-scale emission, when present, usually appears as outer double lobes fed by twin jets. These radio structures can be understood within the context of the beam model of extragalactic radio sources. The compiled radio data also reveal that the vast majority of the remaining 204 galaxies in the volume-limited sample have powers less than or the order of 10(21-22) W Hz-1. A new VLA survey of these objects, reported in a companion paper, is designed (1) to image the galaxies already detected as radio sources but lacking VLA images; (2) to search the many as yet undetected galaxies for radio emission at a level more than ten times lower than previous searches; (3) to detect a compact radio core of power approximately 10(20) W Hz-1 within any galaxy in the survey volume; and (4) to extend the radio luminosity function of radio sources in nearby and bright E/SO galaxies to powers of approximately 10(19) W Hz-1.