The association between gas and galaxies -I. CFHT spectroscopy and pair analysis

Simon L. Morris, Buell T. Jannuzi

Research output: Contribution to journalArticlepeer-review

22 Scopus citations


We investigate the relative distribution of the gaseous contents of the Universe (as traced by a sample of Lyα absorbers), and the luminous baryonic matter (as traced by a redshift survey of galaxies in the same volume searched for Lyα absorbers), along 16 lines of sight (LOS) between redshifts 0 and 1. Our galaxy redshift survey was made with the multi-object spectrograph on the Canada-France-Hawaii Telescope and, when combined with galaxies from the literature in the same LOS, gives us a galaxy sample of 636 objects. By combining this with an absorption-line sample of 406 absorbing systems drawn from published works, we are able to study the relationship between gas and galaxies over the latter half of the age of the Universe. A correlation between absorbers and galaxies is detected out to separation of 1.5 Mpc. This correlation is weaker than the galaxy-galaxy correlation. There is also some evidence that the absorbing systems seen in C IV are more closely related to galaxies, although this correlation could be with column density rather than metallicity. The above results are all consistent with the absorbing gas and the galaxies coexisting in dark matter filaments and knots as predicted by current models where the column density of the absorbing gas is correlated with the underlying matter density.

Original languageEnglish (US)
Pages (from-to)1261-1281
Number of pages21
JournalMonthly Notices of the Royal Astronomical Society
Issue number3
StatePublished - Apr 2006


  • Galaxies: haloes
  • Intergalactic medium
  • Quasars: absorption lines

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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