We report the results from an homogeneous analysis of the X-ray ( Chandra ACIS ) data available for a sample of 51 LINER galaxies selected from the catalogue by Carrillo et al .
( 1999 ) and representative of the population of bright LINER sources .
The nuclear X-ray morphology has been classified attending to their nuclear compactness in the hard band ( 4.5–8.0 keV ) into 2 categories : Active Galactic Nuclei ( AGN ) candidates ( with a clearly identified unresolved nuclear source ) and Starburst ( SB ) candidates ( without a clear nuclear source ) .
60 % of the total sample are classified as AGNs , with a median luminosity of { L _ { X } ( 2 - 10 ~ { } keV ) = 2.5 \times 10 ^ { 40 } ~ { } erg~ { } s ^ { -1 } } , which is an order of magnitude higher than that for SB-like nuclei .
The spectral fitting allows to conclude that most of the objects need a non-negligible power-law contribution .
When no spectral fitting can be performed ( data with low signal-to-noise ratio ) , the Color-Color diagrams allow us to roughly estimate physical parameters such as column density , temperature of the thermal model or spectral index for a power-law and therefore to better constrain the origin of the X-ray emission .
All together the X-ray morphology , the spectra and the Color-Color diagrams allow us to conclude that a high percentage of LINER galaxies , at least \approx 60 % , could host AGN nuclei , although contributions from High Mass X-ray Binaries or Ultra-luminous X-ray sources can not be ruled out for some galaxies .