The contribution of lsb galaxies to the local galaxy number density

Abstract

We present the results from a blind optical survey targeted on the Arecibo Hi Strip Survey (AHISS). Object detection and profile fitting of the galaxies were done with automated algorithms. Our final catalogue is diameter-limited and contains 306 galaxies with diameters larger than 18′′; 148 of these galaxies were previously uncatalogued. Thereupon, we estimated the galaxy number density per square degree and compared it with other optical surveys and with the AHISS itself. Our number density is several times higher than the one from the AHISS. We discuss the selection effects for Hi and optical surveys and point out the influence of different search algorithms and size estimation methods at the number density. The contribution of LSB galaxies to the local galaxy number density is about 30 % and thus not negligible.