SPECTROGRAPHIC STUDY OF A LARGE-SAMPLE OF KISO ULTRAVIOLET EXCESS GALAXIES

We discuss the properties of a sample of 137 Kiso ultraviolet-excess g alaxies (KUGs), mostly with compact morphologies, found to have an emi ssion-line spectrum. The spectroscopic material is collected in a sepa rate paper (Augarde et al. 1994). Estimates of the luminosity function , surface and volume densities are derived for two complete subsamples . The large-scale spatial distribution is found to follow the already known large structures in the nearby Universe. We did not find any KUG lying in a known ''void''. Spectrophotometry of the emission lines sh ows that most of the objects are photoionized starbursting galaxies of various degrees of excitation. The range of physical conditions in th e ionized gas is discussed by comparison with classical extragalactic H II regions models. The equivalent widths of oxygen and Hbeta emissio n lines are correlated and their average values are also correlated wi th the estimate of the ultraviolet excess. A discussion of selection e ffects affecting color surveys and objective-prism emission-line surve ys is given. The oxygen abundance distribution among this KUG sample i s found to be comparable to that already derived for other emission-li ne galaxy samples. We have not found any new extremely oxygen-deficien t emission-line galaxy;