An accretion disc origin for the `X-ray broad line region' in 1H0707-495

TL;DR

This study analyzes high-resolution X-ray spectra of 1H0707-495, revealing broad emission lines with velocity shifts indicative of an accretion disc origin, supporting the discline model and offering insights into the X-ray broad line region.

Contribution

It provides the first high-resolution spectral evidence linking broad emission lines to an accretion disc in 1H0707-495, supporting the discline interpretation of its X-ray spectrum.

Findings

Detection of broad emission lines with velocity shifts consistent with an accretion disc.

Absence of line-of-sight ionized wind or warm absorber features.

Support for the discline model of the X-ray spectrum.

Abstract

We use a 380 ks XMM-Newton high-resolution RGS spectrum to look for narrow spectral features from the nuclear environment of 1H0707-495. We do not find any evidence of a line-of-sight ionized wind (warm absorber). We do, however, detect broad emission lines, of width ~5000 km s^-1, consistent with O VIII Ly-alpha, N VII Ly-alpha, C VI Ly-alpha and a Fe XIX/Fe XX/Ne IX He-alpha blend. Intriguingly, these lines have both blueshifted and redshifted components, whose velocity shifts are consistent with an origin in an accretion disc at ~1600 R_g from the black hole. The features can be interpreted as the narrow line cores of the disc reflection spectrum, thus providing independent support for the discline interpretation of the X-ray spectrum of 1H0707-495. We discuss the relevance of our findings for the `X-ray broad line region' in other Seyferts, and for the origins of the optical broad line region itself.