A deep X-ray view of the bare AGN Ark120. IV. XMM-Newton and NuSTAR spectra dominated by two temperature (warm, hot) Comptonization processes

Understand

We perform an X-ray spectral analysis of the brightest and cleanest bare AGN known so far, Ark 120, in order to determine the process(es) at work in the vicinity of the SMBH.

• We present spectral analysis of data from an extensive campaign observing Ark 120 in X-rays with XMM-Newton (4$\times$120 ks, 2014 March 18-24), and NuSTAR (65.5 ks, 2014 March 22).
• During this very deep X-ray campaign, the source was caught in a high flux state similar to the earlier 2003 XMM-Newton observation, and about twice as bright as the lower-flux observation in 2013.
• The spectral analysis confirms the "softer when brighter" behaviour of Ark 120.