The Low Temperature Corona in ESO 511$-$G030 Revealed by NuSTAR and XMM-Newton

TL;DR

This study analyzes the low-temperature corona in the Seyfert 1 galaxy ESO 511-G030 using coordinated XMM-Newton and NuSTAR observations, revealing a stable low-flux state with a broadband spectrum featuring a soft excess, iron emission, and high-energy cutoff.

Contribution

First detailed spectral and variability analysis of ESO 511-G030 combining XMM-Newton and NuSTAR data, exploring models for the soft excess and corona properties.

Findings

The galaxy remained in a low, stable flux state during observations.

The broadband spectrum shows a soft excess, narrow iron Kα line, and high-energy cutoff.

The soft excess can be explained by either a warm Comptonizing corona or relativistic reflection.

Abstract

We present the results from a coordinated XMM-Newton $+$ NuSTAR observation of the Seyfert 1 Galaxy ESO 511$-$G030. With this joint monitoring programme, we conduct a detailed variability and spectral analysis. The source remained in a low flux and very stable state throughout the observation period, although there are slight fluctuations of flux over long timescales. The broadband (0.3-78~keV) spectrum shows the presence of a power-law continuum with a soft excess below 2~keV, a relatively narrow iron K$\alpha$ emission ($\sim$6.4~keV), and an obvious cutoff at high energies. We find that the soft excess can be modeled by two different possible scenarios: a warm ($kT_{\rm e} \sim$ 0.19~keV) and optically thick ($\tau - 18\sim25$) Comptonizing corona or a relativistic reflection from a high-density ($\log [n_{\rm e}/{\rm cm}^{-3}]=17.1 \sim 18.5$) inner disc. All models require a low temperature ($kT_{\rm e} \sim$ 13~keV) for the hot corona.