Article

# High-Redshift Superclustering of QSO Absorption Line Systems on 100 Mpc Scales

09/1996; DOI:doi:10.1086/310371
Source: arXiv

ABSTRACT We have analyzed the clustering of C IV absorption line systems in an extensive new catalog of heavy element QSO absorbers. The catalog permits exploration of clustering over a large range in both scale (from about 1 to over 300 Mpc) and redshift (z from 1.2 to 4.5). We find significant evidence (5.0 sigma) that C IV absorbers are clustered on comoving scales of 100 Mpc and less --- similar to the size of voids and walls found in galaxy redshift surveys of the local universe --- with a mean correlation function $\xi = 0.42 \pm 0.10$ over these scales. We find, on these scales, that the mean correlation function at low (z=1.7), medium (z=2.4), and high redshift (z=3.0) is $\xi=0.40 \pm 0.17$, $0.32 \pm 0.14$, and $0.72 \pm 0.25$, respectively. Thus, the superclustering is present even at high redshift; furthermore, it does not appear that the superclustering scale, in comoving coordinates, has changed significantly since then. We find 7 QSOs with rich groups of absorbers (potential superclusters) that account for a significant portion of the clustering signal, with 2 at redshift $z\sim 2.8$. We find that the superclustering is just as evident if we take $q_0=0.1$ instead of 0.5; however, the inferred scale of clustering is then 240 Mpc , which is larger than the largest scales of clustering known at present. This discrepancy may be indicative of a larger value of $q_0$, and hence $\Omega_0$. The evolution of the correlation function on 50 Mpc scales is consistent with that expected in cosmologies with density parameter ranging from $\Omega_0 =$ 0.1 to 1. Finally, we find no evidence for clustering on scales greater than 100 Mpc ($q_0=0.5$) or 240 Mpc ($q_0=0.1$). Comment: 16 LaTeX pages with 3 encapsulated Postscript figures included, uses AASTeX (v. 4.0) available at ftp://ftp.aas.org/pubs/ , to appear in The Astrophysical Journal Letters

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### Keywords

16 LaTeX pages

50 Mpc scales

Astrophysical Journal Letters

C IV absorbers

C IV absorption line systems

catalog permits exploration

clustering signal

comoving scales

extensive new catalog

galaxy redshift surveys

inferred scale

large range

largest scales

mean correlation function

mean correlation function \$\xi

potential superclusters

rich groups

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superclustering scale