Lyα cooling radiation from high-redshift halos

Zoltán Haiman, Marco Spaans, Eliot Quataert

Research output: Contribution to journalArticlepeer-review

210 Scopus citations


The baryons inside high-redshift halos with virial temperatures T ≳ 104 K cool radiatively as they condense inside dark matter potential wells. We show that the release of the gravitational binding energy, over the halo assembly timescale, results in a significant and detectable Lyα flux. At the limiting line flux ≈10-19 ergs s-1 cm1 arcsec1 of the Next Generation Space Telescope, several sufficiently massive halos, with velocity dispersions σ ≳ 120 km s-1, would be visible per 4′ × 4′ field. The halos would have characteristic angular sizes of ≈10″, would be detectable in a broadband survey out to z ≈ 6-8, and would provide a direct probe of galaxies in the process of forming. They may be accompanied by He+ Lyα emission at the ≈10% level, but remain undetectable at other wavelengths. Our predictions are in good agreement with the recent finding of two Lyα "blobs" at z = 3.1 by Steidel et al.

Original languageEnglish (US)
Pages (from-to)L5-L8
JournalAstrophysical Journal
Issue number1 PART 2
StatePublished - Jul 1 2000
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


  • Cosmology: theory
  • Early universe
  • Galaxies: ISM
  • Galaxies: evolution


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