An XMM-Newton observation of Mkn 3 - a Seyfert galaxy just over the edge

Abstract

A 100-ks XMM-Newton observation of the nearby Seyfert 2 galaxy Mkn 3 offers a unique opportunity to explore the complexity of its X-ray spectrum. We find the ~3-8 keV continuum to be dominated by reflection from cold matter, with fluorescent K-shell lines detected from Ni, Fe, Ca, Ar, S, Si and Mg. At higher energies an intrinsic power-law continuum, with canonical Seyfert 1 photon index, is seen through a near-Compton-thick cold absorber. A soft excess below ~3 keV is found to be dominated by line emission from an outflow of `warm' gas, photoionized and photoexcited by the intrinsically strong X-ray continuum. Measured blueshifts in the strong Fe Kα and OVII and OVIII emission lines are discussed in terms of the properties of the putative molecular torus and ionized outflow.