The Spatial Clustering of ROSAT All-Sky Survey AGNs III. Expanded Sample
  and Comparison with Optical AGNs
  This is the third paper in a series that reports on our investigation of the
clustering properties of AGNs identified in the ROSAT All-Sky Survey (RASS) and
Sloan Digital Sky Survey (SDSS). In this paper, we extend the redshift range to
0.07<z<0.50 and measure the clustering amplitudes of both X-ray and
optically-selected SDSS broad-line AGNs with and without radio detections as
well as for X-ray selected narrow-line RASS/SDSS AGNs. We measure the
clustering amplitude through cross-correlation functions (CCFs) with SDSS
galaxies and derive the bias by applying a halo occupation distribution (HOD)
model directly to the CCFs. We find no statistically convincing difference in
the clustering of X-ray and optically-selected broad-line AGNs, as well as with
samples in which radio-detected AGNs are excluded. This is in contrast to low
redshift optically-selected narrow-line AGNs, where radio-loud AGNs are found
in more massive halos than optical AGNs without a radio-detection. The typical
dark matter halo masses of our broad-line AGNs are log M_DMH/[h^(-1) M_SUN] ~
12.4-13.4, consistent with the halo mass range of typical non-AGN galaxies at
low redshifts. We find no significant difference between the clustering of
X-ray selected narrow-line AGNs and broad-line AGNs. We confirm the weak
dependence of the clustering strength on AGN X-ray luminosity at a ~2 sigma
level. Finally, we summarize the current picture of AGN clustering to z~1.5
based on three dimensional clustering measurements.
