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 ~7keV and a complex excess below 1keV. 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 1keV 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 1-4keV 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 1-4keV, 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.