Parameter dependency on the public X-ray reverberation models kynxilrev and kynrefrev

Abstract

We present a comparative study of the constrained parameters of active galactic nuclei (AGN) made by the public X-ray reverberation model kynxilrev and kynrefrev that make use of the reflection code xillver and reflionx, respectively. By varying the central mass (MBH), coronal height (h), inclination (i), photon index of the continuum emission (Γ) and source luminosity (L), the corresponding lag-frequency spectra can be produced. We select only the simulated AGN where their lag amplitude (τ) and MBH follow the known mass-scaling law. In these mock samples, we show that τ and h are correlated and can possibly be used as an independent scaling law. Furthermore, h (in gravitational units) is also found to be positively scaled with MBH, suggesting a more compact corona in lower-mass AGN. Both models reveal that the coronal height mostly varies between ∼5–15 rg, with the average height at ∼10 rg and can potentially be found from low- to high-mass AGN. Nevertheless, the kynxilrev seems to suggest a lower MBH and h than the kynrefrev. This inconsistency is more prominent in lower-spin AGN. The significant correlation between the source height and luminosity is revealed only by kynrefrev, suggesting the h–L relation is probably model dependent. Our findings emphasize the differences between these reverberation models that raises the question of biases in parameter estimates and inferred correlations.