ﻻ يوجد ملخص باللغة العربية
We present the first study of an Iwasawa-Taniguchi/X-ray Baldwin effect for Compton-thick active galactic nuclei (AGN). We report a statistically significant anti-correlation between the rest-frame equivalent width (EW) of the narrow core of the neutral Fe K$alpha$ fluorescence emission line, ubiquitously observed in the reflection spectra of obscured AGN, and the mid-infrared 12$,mu$m continuum luminosity (taken as a proxy for the bolometric AGN luminosity). Our sample consists of 72 Compton-thick AGN selected from pointed and deep-field observations covering a redshift range of $zsim0.0014-3.7$. We employ a Monte Carlo-based fitting method, which returns a Spearmans Rank correlation coefficient of $rho=-0.28pm0.12$, significant to 98.7% confidence. The best fit found is ${rm log}({rm EW}_{{rm Fe,K}alpha}),propto,-0.08pm0.04,{rm log}(L_{12,mu{rm m}})$, which is consistent with multiple studies of the X-ray Baldwin effect for unobscured and mildly obscured AGN. This is an unexpected result, as the Fe K$alpha$ line is conventionally thought to originate from the same region as the underlying reflection continuum, which together constitute the reflection spectrum. We discuss the implications this could have if confirmed on larger samples, including a systematic underestimation of the line of sight X-ray obscuring column density and hence the intrinsic luminosities and growth rates for the most luminous AGN.
Due to their heavily obscured central engines, the growth rate of Compton-thick (CT) active galactic nuclei (AGN) is difficult to measure. A statistically significant correlation between the Eddington ratio, {lambda}$_{Edd}$, and the X-ray power-law
We present X-ray bolometric correction factors, $kappa_{Bol}$ ($equiv L_{Bol}/L_X$), for Compton-thick (CT) active galactic nuclei (AGN) with the aim of testing AGN torus models, probing orientation effects, and estimating the bolometric output of th
We analyze observations obtained with the Chandra X-ray Observatory of bright Compton thick active galactic nuclei (AGNs), those with column densities in excess of 1.5 x 10^{24} cm^{-2} along the lines of sight. We therefore view the powerful central
We analyzed the spectral shape of the Compton shoulder around the neutral Fe-K$_alpha$ line of the Compton-thick type II Seyfert nucleus of the Circinus galaxy. The characteristics of this Compton shoulder with respect to the reflected continuum and
We have conducted an extensive X-ray spectral variability study of a sample of 20 Compton-thin type II galaxies using broad band spectra from XMM-Newton, Chandra, and Suzaku. The aim is to study the variability of the neutral intrinsic X-ray obscurat