Survey of Bare Active Galactic Nuclei in the local universe (z < 0.2): I. On the origin of Soft-Excess

TL;DR

This study analyzes a sample of 21 bare Seyfert 1 AGNs in the local universe, revealing a strong correlation between the soft-excess and primary continuum luminosities, suggesting a linked origin related to accretion processes.

Contribution

It provides the first detailed spectral analysis of soft-excess in bare AGNs, establishing a tight luminosity correlation and insights into their emission mechanisms.

Findings

Strong correlation between soft-excess and primary continuum luminosities

Soft-excess and primary emission depend similarly on accretion rate

Spectral analysis confirms linked origin of emissions

Abstract

We analyse a sample of 21 `bare' Seyfert~1 Active Galactic Nuclei (AGNs), a sub-class of Seyfert~1s, with intrinsic absorption $\mathrm{N_{H}} \sim 10^{20}~ \mathrm{cm}^{-2}$, in the local universe (z $<$ 0.2) using {\it XMM-Newton} and {\it Swift}/XRT observations. The luminosities of the primary continuum, the X-ray emission in the 3 to 10 keV energy range and the soft-excess, the excess emission that appears above the low-energy extrapolation of the power-law fit of 3 to 10 keV X-ray spectra, are calculated. Our spectral analysis reveals that the long-term intrinsic luminosities of the soft-excess and the primary continuum are tightly correlated $(L_{PC}\propto L_{SE}^{1.1\pm0.04})$. We also found that the luminosities are correlated for each source. This result suggests that both the primary continuum and soft excess emissions exhibit a dependency on the accretion rate in a similar way.