QSO clustering - II. The correlation function of IRAS Seyfert galaxies

Open Access
Publisher Website
Google Scholar
Abstract
We investigate the clustering properties of 192 Seyfert galaxies from the IRAS all-sky survey. Using the spatial correlation function, we detect evidence of Seyfert clustering at the 2σ confidence level at < 10 h–1 Mpc separations, and at the 3σ level at < 20 h–1 Mpc separations. Comparison of the QSO correlation function amplitude at high redshifts, z = 1.4, with that of Seyferts below 10 h–1 comoving Mpc leads us to reject the stable model of AGN clustering evolution at the 4σ level, whereas a commoving model where QSOs randomly sample the galaxy distribution is more consistent. The main uncertainty here now lies in the statistical error on the amplitude of the clustering in the faint QSO surveys at z = 1.4. The Seyfert–QDOT cross-correlation function is measured to be approximately a factor of 2 higher than the QDOT galaxy autocorrelation function, suggesting an enhanced environment for Seyferts with respect to IRAS galaxies, but it is not clear whether this is also the case with respect to optical galaxies. We conclude that the comoving model is probably favoured overall, at least on the r < 10 h–1 Mpc scales investigated here, but it is not yet possible to rule out intermediate models: for example, an enhanced-environment, stable model with ξ(r) = (r/3)–1.8 at z = 1.4, which is statistically consistent with the faint QSO data.

This publication has 0 references indexed in Scilit: