ETD

• active galaxy
• AGN
• changing-look
• mrk 1018
• x-ray

The thesis is about a multi-wavelength study of the changing-look active galaxy Mrk 1018, that underwent significant optical-to-X-ray flux and spectral changes between 2008 and 2012. We performed a systematic analysis of the X-ray observations carried out with XMM-Newton, Chandra and NuSTAR in the period 2005-2019. Moreover, we took advantage of the simultaneous optical/UV data provided by XMM-Newton Optical Monitor to investigate the relations between the optical/UV and X-ray flux changes. Furthermore, photometry from the 2016 observations of the Sloan Digital Sky Survey was considered, in order to test the hypothesis about the presence of a Super Massive Black Hole binary system in Mrk 1018 nucleus. In this context, we analysed also the optical spectrum measured in the same year by the Multi Unit Spectroscopic Explorer installed at the Very Large Telescope. Our study confirms the variable nature of this AGN and relate the X-ray changes to a dimming of the UV luminosity. In addition to this, it seems possible that the host galaxy of Mrk 1018 is merging with a companion, although the connection with the AGN activity is still unknow.