The Space Density of Galaxies through mu_B(0) = 25.0 mag arcsec^{-2}

Abstract

Using the catalog of O&#39;Neil, Bothun, & Schombert (1999), we examine the central surface brightness distribution (phi(mu_B(0))) of galaxies in the 22.0 < mu_B(0) < 25.0 mag arcsec^{-2} range. Taking advantage of having a catalog in which each galaxy has a known central surface brightness, scale length, and redshift, we apply a bi-variate volume correction to the data and extend the surface brightness distribution function by one magnitude, to 25.0 B mag arcsec^{-2}. The result is a flat (slope = 0) surface brightness distribution function from the Freeman value of 21.65 +/- 0.30 to the survey limit of 25.0 mag arcsec^{-2}, more than 11 sigma away. This indicates that a significant percentage of the baryonic content of the universe is likely in potentials only dimly lit by the embedded galaxy.