Resolving the Large‐Scale Spectral Variability of the Luminous Seyfert 1 Galaxy 1H 0419−577: Evidence for a New Emission Component and Absorption by Cold Dense Matter

An XMM-Newton observation of the luminous Seyfert 1 galaxy 1H 0419-577 inSeptember 2002, when the source was in an extreme low-flux state, found a veryhard X-ray spectrum at 1-10 keV with a strong soft excess below ~1 keV.Comparison with an earlier XMM-Newton observation when 1H 0419-577 was `X-raybright' indicated the dominant spectral variability was due to a steep powerlaw or cool Comptonised thermal emission. Four further XMM-Newton observations,with 1H 0419-577 in intermediate flux states, now support that conclusion,while we also find the variable emission component in intermediate statedifference spectra to be strongly modified by absorption in low ionisationmatter. The variable `soft excess' then appears to be an artefact of absorptionof the underlying continuum while the `core' soft emission can be attributed torecombination in an extended region of more highly ionised gas. We note thewider implications of finding substantial cold dense matter overlying (orembedded in) the X-ray continuum source in a luminous Seyfert 1 galaxy.Comment: 34 pages, 15 figures, submitted to Ap