Violence in the dark ages

Robert J. Thacker, Evan Scannapieco, Marc Davis

Research output: Contribution to journalArticlepeer-review

39 Scopus citations


A wide range of observational and theoretical arguments suggest that the universe experienced a period of heating and metal enrichment, most likely from starbursting dwarf galaxies. Using a hydrodynamic simulation, we have conducted a detailed theoretical investigation of this epoch at the end of the cosmological "dark ages." Outflows strip baryons from previralized halos with total masses ≲1010 M, reducing their number density and the overall star formation rate, while pushing these quantities toward their observed values. We show that the metallicity of ≲ 1010 M objects increases with size but with a large scatter, reproducing the metallicity-luminosity relation of dwarf galaxies. Galaxies ≳ 1010 M form with a roughly constant initial metallicity of 10% solar, explaining the observed lack of metal-poor disk stars in these objects. Outflows enrich roughly 20% of the simulation volume, yielding a mean metallicity of 0.3% solar, in agreement with observations of C IV in quasi-stellar object absorption-line systems.

Original languageEnglish (US)
Pages (from-to)836-843
Number of pages8
JournalAstrophysical Journal
Issue number2 I
StatePublished - Dec 20 2002
Externally publishedYes


  • Galaxies: abundances
  • Galaxies: dwarf
  • Galaxies: evolution
  • Galaxies: high-redshift
  • Quasars: absorption lines

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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