X-ray reflection in the NLS1 1H 0707-495

TL;DR

This study models X-ray reflection in the NLS1 galaxy 1H 0707-495, revealing how spectral features and variability are influenced by relativistic effects and changes in the accretion disc's ionisation and emissivity profile.

Contribution

It applies a reflection-dominated model to multiple observations, explaining spectral shifts and variability through relativistic effects and disc ionisation changes, advancing understanding of NLS1 galaxy spectra.

Findings

Spectral drop shifted from 7 keV to 7.5 keV over two years.

Reflection component less variable than the power law.

Spectral variability driven by changes in ionisation and emissivity profile.

Abstract

We apply a reflection-dominated model to the second XMM-Newton observation of the Narrow Line Seyfert 1 galaxy 1H 0707-495. As in the first XMM-Newton observation a sharp spectral drop is detected with energy that has shifted from 7 keV to 7.5 keV in two years. The drop is interpreted in terms of relativistically blurred ionised reflection from the accretion disc, while the energy shift can be accounted for by changes in the ionisation state and, more importantly, emissivity profile on the disc. A flatter emissivity profile during the second higher flux observation reduces gravitational redshift effects, therefore shifting the edge to higher energy. Remarkably, ionised disc reflection and the associated power law continuum provide a reasonable description of the broadband spectrum, including the soft excess. Considering both observations, the spectral variability in 1H 0707-495 appears to be due to the interplay between these two spectral components. The reflection component in the second observation is significantly less variable than the power law. Changes of the emissivity profile, spectral shape and variability properties (such as the rms spectrum) within the two observations are all consistent with a recently proposed model in which relativistic effects in the very inner regions of the nucleus play a major role.