AGN clustering in the local Universe: an unbiased picture from Swift-BAT
  We present the clustering measurement of hard X-ray selected AGN in the local
Universe. We used a sample of 199 sources spectroscopically confirmed detected
by Swift-BAT in its 15-55 keV all-sky survey. We measured the real space
projected auto-correlation function and detected a signal significant on
projected scales lower than 200 Mpc/h. We measured a correlation length of
r0=5.56+0.49-0.43 Mpc/h and a slope {\gamma}=1.64-0.08 -0.07. We also measured
the auto-correlation function of Type I and Type II AGN and found higher
correlation length for Type I AGN. We have a marginal evidence of luminosity
dependent clustering of AGN, as we detected a larger correlation length of
luminous AGN than that of low luminosity sources. The corresponding typical
host DM halo masses of Swift-BAT are log(MDMH) 12-14 h^-1 M/M_sun, depending on
the subsample. For the whole sample we measured log(MDMH)\sim 13.15 h-1 M/M_sun
which is the typical mass of a galaxy group. We estimated that the local AGN
population has a typical lifetime tau_AGN \sim 0.7 Gyr, it is powered by SMBH
with mass MBH \sim 1-10x10^8 M_\odot and accreting with very low efficiency,
log(epsilon)-2.0. We also conclude that local AGN host galaxies are typically
red-massive galaxies with stellar mass of the order 2-80x10^10 h^-1 M_sun. We
compared our results with clustering predictions of merger-driven AGN
triggering models and found a good agreement.
