2000/11/21 by Ji Meng Loh, Loh, Ji Meng, Jean M. Quashnock +3
Earth and Planetary Sciences · Environmental Science · Physics and Astronomy · #Astrophysics (astro-ph) #Atmospheric Ozone and Climate #Atmospheric and Environmental Gas Dynamics #Data Analysis #FOS: Physical sciences #Statistics and Probability (physics.data-an) #astro-ph #physics.data-an
paper · pdf · doi:10.48550/arxiv.astro-ph/0011397
24 pages, LaTeX (AASTex v5.0). Includes 7 Encapsulated PostScript figures. Submitted to the Astrophysical Journal
arxiv created 2000/11/21 · openalex publication_date 2000/11/21 · arxiv updated 2009/12/01 · openalex created_date 2022/09/30 · openalex updated_date 2026/07/28
We examine the three-dimensional clustering of C IV absorption-line systems,\nusing an extensive catalog of QSO heavy-element absorbers drawn from the\nliterature. We measure clustering by a volume-weighted integral of the\ncorrelation function called the reduced second-moment measure, and include\ninformation from both along and across QSO lines of sight, thus enabling a full\ndetermination of the three-dimensional clustering of absorbers, as well as a\ncomparison of line- and cross-line-of-sight clustering properties. Here we\npresent the three-dimensional reduced second-moment estimator for a\nthree-dimensional point process probed by one-dimensional lines of sight, and\napply our algorithm to a sample of 345 C IV absorbers with median redshift of\n2.2, drawn from the spectra of 276 QSOs. We confirm the existence of\nsignificant clustering on comoving scales up to 100 Mpc, and find that the\nadditional cross-line-of-sight information strengthens the evidence for\nclustering on scales from 100 Mpc to 150 Mpc. There is no evidence of absorber\nclustering along or across lines of sight for scales from 150 Mpc to 300 Mpc.\nWe show that with a 300-times larger catalog, such as that to be compiled by\nthe Sloan Digital Sky Survey (100,000 QSOs), use of the full three-dimensional\nestimator and cross-line-of-sight information will substantially increase\nclustering sensitivity. We find that standard errors are reduced by an\nadditional factor of 2 to 20 on scales of 30 to 200 Mpc, effectively increasing\nthe sample size by an extra factor of 4 to 400 at large distances.\n