Line, LINER, linest - from micro-AGN to ultra-luminous LINERs. One and
  the same?
  This paper compares the optical spectra of a wide range of galaxies
categorised as members of the Low Ionisation Nuclear Emission Region (LINER)
class of active galactic nuclei (AGN). LINERs are defined by emission spectra
with relatively faint high ionisation lines (compared to other AGN classes).
The gas emission luminosity ranges from the weak flux emanating from some
nearby galactic nuclei all the way to extremely luminous radio galaxies, where
the line emission can completely dominate the host galaxy starlight component.
In this study I analyse the Sloane Digital Sky Survey optical spectra of 15
LINERS identified in the course of the preparation of the new edition of the
ZORROASTER AGN catalogue, spanning the largest possible luminosity range. I
compare relative emission line strengths, focusing on uncommonly analysed
ratios such as those involving [N I], line widths, profiles and even the
spectral features of the host galaxy stellar continuum. The study identifies
possible luminosity dependent trends in the spectral properties of the studied
objects. Possible reasons are presented to rationalise these trends, and the
paper concludes with a discussion regarding the uniformity of the LINER class.
