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ABSTRACT In this work, we present the results of a detailed X-ray spectral analysis of the brightest active galactic nuclei (AGNs) detected in the XMM–Newton 1. 75 Ms Ultra Narrow Deep Field. We analysed 23 AGNs that have a luminosity range of 10^42 \!-\! 10^46\, erg\, s^-1 in the 2 \!-\! 10\, keV energy band, redshifts up to 2. 66, and 10\, 000 X-ray photon counts in the 0. 3 \!-\! 10\, keV energy band. Our analysis confirms the ‘Iwasawa–Taniguchi effect, ’ an anticorrelation between the X-ray luminosity (Lₓ) and the Fe–k equivalent width (EW ₅₄) possibly associated with the decreasing of the torus covering factor as the AGN luminosity increases. We investigated the relationship among black hole mass (M ₁₇), Lₓ, and X-ray variability, quantified by the Normalized Excess Variance (² ₑ₌ₒ). Our analysis suggest an anticorrelation in both M ₁₇ - ² ₑ₌ₒ and Lₓ- ² ₑ₌ₒ relations. The first is described as ² ₑ₌ₒ M^-0. 26 0. 05 ₁₇, while the second presents a similar trend with ² ₑ₌ₒ Lₗ^-0. 31 0. 04. These results support the idea that the luminosity–variability anticorrelation is a byproduct of an intrinsic relationship between the BH mass and the X-ray variability, through the size of the emitting region. Finally, we found a strong correlation among the Eddington ratio (₄₃₃), the hard X-ray photon index (), and the illumination factor (A), which is related to the ratio between the number of Compton scattered photons and the number of seed photons. The (₄₃₃) - - (A) plane could arise naturally from the connection between the accretion flow and the hot corona.
Elías-Chávez et al. (Thu,) studied this question.