  We combine multiwavelength data in the AEGIS-XD and C-COSMOS surveys to
measure the typical dark matter halo mass of X-ray selected AGN
[Lx(2-10keV)>1e42 erg/s] in comparison with far-infrared selected star-forming
galaxies detected in the Herschel/PEP survey (PACS Evolutionary Probe; Lir>1e11
solar) and quiescent systems at z~1. We develop a novel method to measure the
clustering of extragalactic populations that uses photometric redshift
Probability Distribution Functions in addition to any spectroscopy. This is
advantageous in that all sources in the sample are used in the clustering
analysis, not just the subset with secure spectroscopy. The method works best
for large samples. The loss of accuracy because of the lack of spectroscopy is
balanced by increasing the number of sources used to measure the clustering. We
find that X-ray AGN, far-infrared selected star-forming galaxies and passive
systems in the redshift interval 0.6<z<1.4 are found in halos of similar mass,
$\log M_{DMH}/(M_{\odot}\,h^{-1})\approx13.0$. We argue that this is because
the galaxies in all three samples (AGN, star-forming, passive) have similar
stellar mass distributions, approximated by the J-band luminosity. Therefore
all galaxies that can potentially host X-ray AGN, because they have stellar
masses in the appropriate range, live in dark matter haloes of $\log
M_{DMH}/(M_{\odot}\,h^{-1})\approx13.0$ independent of their star-formation
rates. This suggests that the stellar mass of X-ray AGN hosts is driving the
observed clustering properties of this population. We also speculate that
trends between AGN properties (e.g. luminosity, level of obscuration) and large
scale environment may be related to differences in the stellar mass of the host
galaxies.
