Accretion Properties of A Sample of Hard X-ray (<60keV) Selected Seyfert 1 Galaxies

TL;DR

This study investigates accretion properties of 42 hard X-ray selected Seyfert 1 galaxies, revealing correlations between X-ray luminosity, black hole mass, and emission line features, with implications for understanding AGN physics.

Contribution

It provides new insights into the accretion characteristics of hard X-ray selected AGNs, emphasizing the correlation between X-ray luminosity, black hole mass, and emission line properties, based on a larger, harder X-ray sample.

Findings

Strong correlation between hard X-ray (3-20 keV) and bolometric/line luminosity.

Inverse Baldwin effect observed in Hβ emission line.

Hard X-ray AGNs are biased towards luminous, high Eddington ratio, low column density objects.

Abstract

We examine the accretion properties in a sample of 42 hard (3-60keV) X-ray selected nearby broad-line AGNs. The energy range in the sample is harder than that usually used in the similar previous studies. These AGNs are mainly complied from the RXTE All Sky Survey (XSS), and complemented by the released INTEGRAL AGN catalog. The black hole masses, bolometric luminosities of AGN, and Eddington ratios are derived from their optical spectra in terms of the broad H$\beta$ emission line. The tight correlation between the hard X-ray (3-20keV) and bolometric/line luminosity is well identified in our sample. Also identified is a strong inverse Baldwin relationship of the H$\beta$ emission line. In addition, all these hard X-ray AGNs are biased toward luminous objects with high Eddington ratio (mostly between 0.01 to 0.1) and low column density ($<10^{22} \mathrm{cm^{-2}}$), which is most likely due to the selection effect of the surveys. The hard X-ray luminosity is consequently found to be strongly correlated with the black hole mass. We believe the sample completeness will be improved in the next few years by the ongoing Swift and INTEGRAL missions, and by the next advanced missions, such as NuSTAR, Simbol-X, and NeXT. Finally, the correlation between RFe (=optical FeII/H$\beta$) and disk temperature as assessed by $T\propto (L/L_{\mathrm{Edd}})M_{\mathrm{BH}}^{-1}$ leads us to suggest that the strength of the FeII emission is mainly determined by the shape of the ionizing spectrum.