2001/12/03 by Joop Schaye, Schaye, Joop
Engineering · Physics and Astronomy · #Astrophysics (astro-ph) #FOS: Physical sciences #Satellite Image Processing and Photogrammetry #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/0112022
4 pages, 2 figures, to appear in the proceedings of the XVIIth IAP Colloquium, Paris, June 2001
arxiv created 2001/12/03 · openalex publication_date 2001/12/03 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
It is shown that many properties of Ly-alpha forest absorbers can be derived using simple physical arguments. Analytical expressions are derived for the density and the size of an absorber as a function of its neutral hydrogen column density, which agree well with both observations and hydrodynamical simulations. An expression is presented to compute OmegaIGM from the observed column density distribution, independent of the overall shape of the absorbers. Application to the observed column density distribution shows that at high redshift most of the baryons are in the forest and suggests a simple interpretation for its shape and evolution.