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

Abstract

We use a 380-ks X-ray Multi-Mirror Mission-Newton (XMM-Newton) high-resolution Reflection Grating Spectrometer (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 kms^-1, consistent with OVIII Lyα, NVII Lyα, CVI Lyα and an FeXIX/FeXX/NeIX Heα 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.