The mass fraction of AGN and the Fundamental Plane of black hole
  activity from a large X-ray selected sample of LINERs
  A sample of 576 X-ray selected LINERs was constructed by combining data from
the 3XMM-DR4 and SDSS-DR7 catalogues. The sample was used to investigate the
fraction of galaxies hosting a LINER, finding that the fraction is a strong
function of both stellar mass and black hole mass (scaling to the power of 1.6
+/- 0.2 and 0.6 +/- 0.1 respectively) and that it rises close to unity at the
highest black hole masses and lowest X-ray luminosities. After obtaining radio
flux densities from the FIRST survey, the sample was also used to investigate
the Fundamental Plane of black hole activity - a scale-invariant relationship
between black hole mass, X-ray luminosity and radio luminosity that is believed
to hold across at least nine orders of magnitude of mass. There are key
advantages in using only LINERs for the derivation as these are the
counterparts of the "low-hard" X-ray binaries for which the relationship is
tightest. The Fundamental Plane was found to be log (L_R / erg/s) = (0.65 +/-
0.07) log (L_X / 10^42 erg/s) + (0.69 +/- 0.10) log (M_BH / 10^8 M_solar) +
(38.35 +/- 0.10). The scatter around the plane was 0.73 +/- 0.03 dex, too large
to suggest that the Fundamental Plane can be used as a tool to estimate black
hole mass from the observables of X-ray and radio luminosity. The black hole
mass scaling is sensitive to the slope of the mass - velocity dispersion
relation and, in order to achieve consistency with X-ray binaries, the analysis
favours a steep gradient for this relationship, as found in recent research.
