2 The sample

The present work refers to the 191 galaxies within the lists I and II of the UCM Survey. The main features of each galaxy as well as the observation parameters and reduction techniques were listed in Paper I.

The UCM Survey galaxies lie at an averaged redshift of 0.026. The sample is dominated by low-excitation, high-metallicity starburst-like galaxies (57% of the sample); high-excitation, low-metallicity HII-like galaxies are also present (32%) with a fraction of AGN objects (8%) (Gallego et al. 1996). The averaged B magnitude and standard deviation of the sample are $16.1\pm 1.1$ and the mean B-r colour $0.73\pm 0.41$ (Pérez-González et al. 2000), corresponding to a morphological type of Sbc, according to Fukugita et al. (1995).