The changing source of X-ray reflection in the radio-intermediate Seyfert 1 galaxy III Zw 2

TL;DR

This study analyzes 17 years of X-ray data from III Zw 2, revealing spectral variability possibly linked to jet precession and changing illumination of the accretion disc and torus.

Contribution

It provides the first long-term X-ray spectral analysis of III Zw 2, suggesting a connection between jet precession and spectral changes.

Findings

Spectral differences observed between 2000 and 2011 despite similar flux levels.

2000 spectrum shows broad Gaussian and soft excess, 2011 spectrum shows narrow line.

Variability may be due to jet precession affecting the illumination of accretion structures.

Abstract

We report on X-ray observations of the radio-intermediate, X-ray bright Seyfert 1 galaxy, III Zw 2, obtained with XMM-Newton, Suzaku, and Swift over the past 17-years. The source brightness varies significantly over yearly time scales, but more modestly over periods of days. Pointed observations with XMM-Newton in 2000 and Suzaku in 2011 show spectral differences despite comparable X-ray fluxes. The Suzaku spectra are consistent with a power law continuum and a narrow Gaussian emission feature at ~6.4 keV, whereas the earlier XMM-Newton spectrum requires a broader Gaussian profile and soft-excess below ~2 keV. A potential interpretation is that the primary power law emission, perhaps from a jet base, preferentially illuminates the inner accretion disc in 2000, but the distant torus in 2011. The interpretation could be consistent with the hypothesised precessing radio jet in III Zw 2 that may have originated from disc instabilities due to an ongoing merging event.