The non-linear X-ray/UV relation in active galactic nuclei: contribution of instrumental effects on the X-ray variability

Understand

We have recently demonstrated that the non-linear relation between ultraviolet and X-ray luminosity in quasars is very tight (with an intrinsic dispersion of ~0.2 dex), once contaminants (e.g.

• dust reddening, X-ray absorption), variability, and differences in the active galactic nuclei (AGN) physical properties are taken into account.
• This relation has thus the great potential to advance our understanding in both supermassive black hole accretion physics and observational cosmology, by targeting a single class of objects.
• Here we focus on the various contributions to the observed X-ray variability in a homogenous sample of 791 quasars selected from SDSS-DR7 with X-ray data from the 3XMM-DR7 source catalogue.