Galaxies Found at 21 CM in a Cosmic Void

Abstract

Recent redshift surveys indicate that the vast majority of galaxies included in magnitude-limited samples appear to lie on the surfaces of “bubbles” that surround regions of low galaxy density, known as “voids”. There is no hard evidence, however, that these voids are not populated by low surface brightness (LSB) galaxies. One constraint on models of large-scale structure formation is the relative distributions of the LSB and high surface brightness (HSB) galaxies. For instance, biased cold dark matter models predict that LSB galaxies should be more uniformly distributed than HSB galaxies. In this scenario, cosmic voids could be filled with LSB objects while HSB objects would be found preferentially in the denser environment of the shells.