A broadband X-ray spectral study of the Seyfert 1 galaxy ESO 141--G055 with XMM-Newton and NuSTAR

TL;DR

This study analyzes the broadband X-ray spectra of Seyfert 1 galaxy ESO 141--G055 using XMM-Newton and NuSTAR, revealing a soft excess, narrow Fe line, and Compton hump, with models suggesting a maximally spinning black hole.

Contribution

It provides a comprehensive spectral analysis of ESO 141--G055, comparing models for the soft excess and exploring the black hole spin and reflection components.

Findings

Soft excess explained by two models: blurred reflection and thermal Comptonisation.

No broad Fe line detected, suggesting either absence or extreme blurring.

Black hole spin inferred to be near maximal (a>0.96).

Abstract

We have extensively studied the broadband X-ray spectra of the source ESO~141--G055 using all available \xmm{} and \nustar{} observations. We detect a prominent soft excess below 2 keV, a narrow Fe line and a Compton hump (>10 keV). The origin of the soft excess is still debated. We used two models to describe the soft excess: the blurred reflection from the ionized accretion disk and the intrinsic thermal Comptonisation model. We find that both of these models explain the soft excess equally well. We confirm that we do not detect any broad Fe line in the X-ray spectra of this source, although both the physical models prefer a maximally spinning black hole scenario (a$>$0.96). This may mean that either the broad Fe line is absent or blurred beyond detection. The Eddington rate of the source is estimated to be $\lambda_{Edd} \sim 0.31$. In the reflection model, the Compton hump has a contribution from both ionized and neutral reflection components. The neutral reflector which simultaneously describes the narrow Fe K$\alpha$ and the Compton hump has a column density of $\rm N_{H} \geq 7\times 10^{24} \rm cm^{-2} $. In addition, we detect a partially covering ionized absorption with ionization parameter $\log \xi/\rm erg cm s^{-1}$ = $0.1^{+0.1}_{-0.1}$ and column density $\rm N_{H} =20.6^{+1.0}_{-1.0}\times 10^{22} \rm cm^{-2}$ with a covering factor of $0.21^{+0.01}_{-0.01}$.