Investigating the reflection contribution to the X-ray emission of Ton S180

TL;DR

This study examines the reflection contribution to the X-ray emission of Ton S180, demonstrating the effectiveness of dual-reflector models in explaining its spectral features and stability over time.

Contribution

It provides a detailed application of dual-reflector reflection models to Ton S180, highlighting their spectral flexibility and potential in understanding soft X-ray excess in active galaxies.

Findings

Successful fit with dual-reflector model including ionized and cold components

Spectral stability over several years suggests a consistent physical process

Ton S180's soft excess challenges reflection models but demonstrates their versatility

Abstract

There is now growing evidence that the soft X-ray excess is almost ubiquitous among unobscured active galaxies. In spite of the various interpretations that have been considered in the last years, the nature of this foremost spectral feature is not firmly established yet. In this context, we review from a reflection perspective the three highest-quality X-ray observations of the narrow-line Seyfert 1 galaxy Tonantzintla S180, obtained by XMM-Newton and Suzaku. The X-ray spectrum of Ton S180 shows only moderate variations over a time span of several years, suggesting that the same physical process accounts for the bulk of the broad-band X-ray emission at the different epochs, and that the properties of the X-ray source are fairly stable. We have successfully applied in our spectral analysis a dual-reflector model, consisting of two separate components: one arises from the surface of the accretion disc, is highly ionized and blurred by relativistic effects; the other is cold, quite faint, and can be associated with a distant reprocessor. Due to the strength and the nearly power-law shape of its soft excess emission, Ton S180 is one of the most challenging sources to test the X-ray reflection scenario. In this work we provide a clear illustration of the great potential and spectral flexibility of blurred reflection models, while discussing some of their current limitations and possible shortcomings.