The Space Density of Galaxies through µB(0) = 25.0 mag/arcsec²

Authors: Karen O'Neil, & G. D. Bothun

Published:The Astrophysical Journal, Vol 529, pg 811 (2000)


Using the catalog of O'Neil, Bothun, & Schombert (1999), we examine the central surface brightness distribution (phi(µ(0))) of galaxies in the 22.0 < µ(0) < 25.0 B mag/arcsec² 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/arcsec². 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/arcsec², 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.

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