2015/08/31 by L. Keek, D. R. Ballantyne · 57 citations
Physics and Astronomy · #Accretion (finance) #Active galactic nucleus #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Corona (planetary geology) #Eddington luminosity #Emission spectrum #Galaxy #Ion #Ionization #Physics #Spectral line #Supermassive black hole #astro-ph.HE
paper · pdf · doi:10.1093/mnras/stv2882
published in Monthly Notices of the Royal Astronomical Society 456(3), 2722-2734 (Oxford University Press) · 14 pages, 11 figures, 3 tables, accepted for publication in MNRAS
arxiv created 2015/12/12 · arxiv updated 2015/12/15 · openalex publication_date 2015/12/31 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Active galactic nuclei host an accretion disc with an X-ray producing corona around a supermassive black hole. In bright sources, such as the Seyfert 1 galaxy Mrk 335, reflection of the coronal emission off the accretion disc has been observed. Reflection produces spectral features such as an Fe Kα emission line, which allow for properties of the inner accretion disc and the corona to be constrained. We perform a multi-epoch spectral analysis of all XMM–Newton, Suzaku, and NuSTAR observations of Mrk 335, and we optimize our fitting procedure to unveil correlations between the Eddington ratio and the spectral parameters. We find that the disc's ionization parameter correlates strongly with the Eddington ratio: the inner disc is more strongly ionized at higher flux. The slope of the correlation is less steep than previously predicted. Furthermore, the cut-off of the power-law spectrum increases in energy with the Eddington ratio, whereas the reflection fraction exhibits a decrease. We interpret this behaviour as geometrical changes of the corona as a function of the accretion rate. Below ∼10 per cent of the Eddington limit, the compact and optically thick corona is located close to the inner disc, whereas at higher accretion rates the corona is likely optically thin and extends vertically further away from the disc surface. Furthermore, we find a soft excess that consists of two components. In addition to a contribution from reflection in low ionization states, a second component is present that traces the overall flux.