The low-redshift Lyα forest towards 3C 273

Gerard M. Williger, Robert F. Carswell, Ray J. Weymann, Edward B. Jenkins, Kenneth R. Sembach, Todd M. Tripp, Romeel Davé, Lutz Haberzettl, Sara R. Heap

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


We present an analysis of the Ly. α forest towards 3C 273 from the Space Telescope Imaging Spectrograph at ∼7 km s. -1 resolution, along with reprocessed data from the Far Ultraviolet Spectroscopic Explorer. The high ultraviolet flux of 3C 273 allows us to probe the weak, low- z absorbers. The main sample consists of 21 H i absorbers that we could discriminate to a sensitivity of the redshift density for absorbers with is ∼ 1.5σ below the mean for other lines of sight; for, it is consistent with numerical model predictions. The Doppler parameter distribution is consistent with other low- z samples. We find no evidence for a break in the column density power-law distribution to a broad Ly. α absorber is within Δv≤ 50 km s. -1 and 1.3 local-frame Mpc of two ∼ 0.5L* galaxies, with an O vi absorber ∼700 km s. -1 away, similarly close to three galaxies and indicating overdense environments. We detect clustering on the Δv < 1000 km s. -1 scale at 3.4σ significance for, consistent with the level predicted from hydrodynamical simulations, and indication for a Ly. α forest void at 0.09 < z < 0.12. We find at least two components for the z= 0.0053 Virgo absorber, but the total column is not significantly changed.

Original languageEnglish (US)
Pages (from-to)1736-1758
Number of pages23
JournalMonthly Notices of the Royal Astronomical Society
Issue number3
StatePublished - Jul 2010
Externally publishedYes


  • Cosmology: observations
  • Intergalactic medium
  • Quasars: absorption lines

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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