Squelched Galaxies and Dark Halos

R. Brent Tully, Rachel S. Somerville, Neil Trentham, Marc A. W. Verheijen

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126 Citations (Scopus)


There is accumulating evidence that the faint end of the galaxy luminosity function might be very different in different locations. The luminosity function might be rising in rich clusters and flat in regions of low density. If galaxies form according to the model of hierarchical clustering, then there should be many small halos compared to the number of big halos. If this theory is valid, then there must be a mechanism that eliminates at least the visible component of galaxies in low-density regions. A plausible mechanism is photoionization of the intergalactic medium at a time before the epoch that most dwarf galaxies form in low-density regions but after the epoch of formation for similar systems that ultimately end up in rich clusters. The dynamical timescales are found to accommodate this hypothesis in a flat universe with Ωm
Original languageEnglish
Pages (from-to)573-581
Number of pages9
JournalThe Astrophysical Journal
Issue number2
Publication statusPublished - 1-Apr-2002
Externally publishedYes


  • Cosmology: Dark Matter
  • Galaxies: Formation
  • Galaxies: Luminosity Function
  • Mass Function

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