Coronal Properties of Low-Accreting AGNs using Swift, XMM-Newton and NuSTAR Observations

TL;DR

This study analyzes the X-ray spectra of 30 low-accreting AGNs using multiple space telescopes to understand their coronal properties and how these relate to accretion and jet activity.

Contribution

It provides the first comprehensive broadband spectral analysis of low-Eddington ratio AGNs, revealing correlations among coronal parameters and jet luminosity.

Findings

Hot electron temperature correlates with cutoff energy similarly to high-accretion AGNs.

No correlation between Eddington ratio and photon index.

Jet luminosity scales with bolometric luminosity as L_jet ∝ L_bol^0.7.

Abstract

We studied the broadband X-ray spectra of {\it Swift}/BAT selected low-accreting AGNs using the observations from {\it XMM-Newton}, {\it Swift}, and {\it NuSTAR} in the energy range of $0.5-150$~keV. Our sample consists of 30 AGNs with Eddington ratio, $\lambda_{\rm Edd}<10^{-3}$. We extracted several coronal parameters from the spectral modelling, such as the photon index, hot electron plasma temperature, cutoff energy, and optical depth. We tested whether there exists any correlation/anti-correlation among different spectral parameters. We observe that the relation of hot electron temperature with the cutoff energy in the low accretion domain is similar to what is observed in the high accretion domain. We did not observe any correlation between the Eddington ratio and the photon index. We studied the compactness-temperature diagram and found that the cooling process for extremely low-accreting AGNs is complex. The jet luminosity is calculated from the radio flux, and observed to be related to the bolometric luminosity as $L_{\rm jet} \propto L_{\rm bol}^{0.7}$, which is consistent with the standard radio-X-ray correlation.