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

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$\hat{I}\pm$ emission ($\sim$6.4~keV), and an obvious cutoff at high energies. We find that the soft excess can be modeled by two different possible scenarios: a warm ($k{T}_{\mathrm{e}}\sim$ 0.19~keV) and optically thick ($\ddot{I}„-18\sim 25$) Comptonizing corona or a relativistic reflection from a high-density ($\log [n_{\mathrm{e}}/{\mathrm{cm}}^{-3}]=17.1\sim 18.5$) inner disc. All models require a low temperature ($k{T}_{\mathrm{e}}\sim$ 13~keV) for the hot corona.

18 pages, 15 figures. v2: refereed version