Constraints on the spacetime metric around seven "bare" AGNs using X-ray reflection spectroscopy

Understand

We present the study of a sample of seven "bare" active galactic nuclei (AGN) observed with Suzaku.

• We interpret the spectrum of these sources with a relativistic reflection component and we employ our model RELXILL_NK to test the Kerr nature of their supermassive black holes.
• We constrain the Johannsen deformation parameters $\alpha_{13}$ and $\alpha_{22}$, in which the Kerr metric is recovered when $\alpha_{13} = \alpha_{22} = 0$.
• All our measurements are consistent with the hypothesis that the spacetime geometry around these supermassive objects is described by the Kerr solution.