SIMBAD references

We present flux-calibrated spectra in the range 3500 to 8000 Å for the nuclear regions of 250 galaxies and H I 21 cm line profiles for 238 galaxies selected from the catalog of low surface brightness galaxies identified in Automated Plate Measuring Facility (APM) scans of UK Schmidt Telescope survey plates. For the optical spectra, common nebular absorption- and emission-line equivalent widths and emission-line fluxes were measured with typical errors of about 20%. H I mass and velocity widths were measured from the 21 cm line emission, with 15% accuracy. Galaxies in this study span over 6 mag in surface brightness. Only about 20% of these galaxies show spectroscopic evidence of active galactic nuclei. Derived quantities such as synthetic colors, metallicity, star formation rate, the ratio of neutral hydrogen mass to blue light, and gas mass fraction are presented in a companion paper.