X-ray spectral variability of LINERs selected from the Palomar sample

Hernandez-Garcia, L.; González-Martín, O.; Masegosa, J.; Márquez, I.
Bibliographical reference

The X-ray Universe 2014, edited by Jan-Uwe Ness. Online at http://xmm.esac.esa.int/external/xmm_science/workshops/2014symposium/, id.257

Advertised on:
7
2014
Number of authors
4
IAC number of authors
1
Citations
0
Refereed citations
0
Description
Variability in active galactic nuclei (AGN) has been discovered at X-ray, UV, and radio frequencies on timescales from hours to years, being one of their most important features. Among the AGN family and according to theoretical studies, low-ionization nuclear emission line region (LINER) nuclei would be variable objects at long timescales because of their large black hole masses and low accretion rates. Our aim is to investigate the spectral X-ray variability in LINERs, leading to an understanding of the nature of this kind of objects, including their accretion mechanism. We selected 18 LINERs from the Palomar sample, and used Chandra and XMM-Newton public archives to analyze their X-ray spectral properties at different epochs with timescales of years. Spectral modeling allowed us to investigate the parameter(s) responsible for the variations. The main result from the analysis is that long term spectral variability is very common, mostly related to the nuclear power at hard (2-10 keV) energies.