The optical to X-ray spectrum of the broad-line ultrasoft AGN RE J2248-511 |
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Authors: | R.L.C. Starling E.M. Puchnarewicz E. Romero-Colmenero K.O. Mason |
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Affiliation: | aMullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey RH5 6NT, UK bSouth African Astronomical Observatory, P.O. Box 9, Observatory, 7395 South Africa |
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Abstract: | We present a series of monitoring observations of the ultrasoft broad-line Seyfert galaxy RE J2248-511 with XMM-Newton. Previous X-ray observations showed a transition from a very soft state to a harder state five years later. We find that the ultrasoft X-ray excess has re-emerged, yet there is no change in the hard power-law. Reflection models with a reflection fraction of 15, and Comptonisation models with two components of different temperatures and optical depths (kT1 = 83 keV, T1 = 30 eV, τ1 = 0.8; KT2 = 3.5 keV, T2 = 60 eV, τ2 = 2.8) can be fit to the spectrum, but cannot be constrained. The best representation of the spectrum is a model consisting of two blackbodies (kT1 = 0.09 ± 0.01 keV, kT2 = 0.21 ± 0.03 keV) plus a power-law (Γ = 1.8 ± 0.08). We also present simultaneous optical and infrared data showing that the optical spectral slope also changes dramatically on timescales of years. If the optical to X-ray flux comes primarily from a Comptonised accretion disk we obtain estimates for the black hole mass , accretion rate and inclination cos(i) 0.8 of the disk. |
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Keywords: | Optical to X-ray spectrum AGN RE J2248-511 Astrophysics |
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