Broad iron L line and X-ray reverberation in 1H0707-495

Abstract

A detailed analysis of a long XMM–Newton observation of the narrow-line type 1 Seyfert galaxy 1H0707-495 is presented, including spectral fitting, spectral variability and timing studies. The two main features in the spectrum are the drop at ∼7 keV and a complex excess below 1 keV. These are well described by two broad, K and L, iron lines. Alternative models based on absorption, although they may fit the high-energy drop, cannot account for the 1 keV complexity and the spectrum as a whole. Spectral variability shows that the spectrum is composed of at least two components, which are interpreted as a power law dominating between 1–4 keV and a reflection component outside this range. The high count rate at the iron L energies has enabled us to measure a significant soft lag of ∼30 s between 0.3–1 and 1–4 keV, meaning that the direct hard emission leads the reflected emissions. We interpret the lag as a reverberation signal originating within a few gravitational radii of the black hole.