An X-ray view of 82 LINERs with Chandra and XMM-Newton data
  We present the results of an homogeneous X-ray analysis for 82 nearby LINERs
selected from the catalogue of Carrillo et al. (1999). All sources have
available Chandra (68 sources) and/or XMM-Newton (55 sources) observations.
This is the largest sample of LINERs with X-ray spectral data (60 out of the 82
objects) and significantly improves our previous analysis based on Chandra data
for 51 LINERs (Gonzalez-Martin et al. 2006). It increases both the sample size
and adds XMM-Newton data. New models permit the inclusion of double absorbers
in the spectral fits. Nuclear X-ray morphology is inferred from the compactness
of detected nuclear sources in the hard band (4.5-8.0 keV). Sixty per cent of
the sample shows a compact nuclear source and are classified as AGN candidates.
The spectral analysis indicates that best fits involve a composite model:
absorbed primary continuum and (2) soft spectrum below 2 keV described by an
absorbed scatterer and/or a thermal component. The resulting median spectra
parameters and their standard deviations are: G=2.11, <kT>=0.54 keV,
<log(NH1)>=21.32 and <log(NH2)>=21.93. We complement our X-ray results with our
analysis of HST optical images and literature data on emission lines, radio
compactness and stellar population. Adding all these multiwavelength data, we
conclude that evidence do exist supporting the AGN nature of their nuclear
engine for 80% of the sample (66 out of 82 objects).
