An XMM-Newton observation of the luminous Seyfert 1 galaxy Markarian 509

We present the spectral analysis of an early XMM-Newton observation of the luminous Seyfert 1 galaxy Mrk 509. We find the hard (2-10 keV) continuum slope, including reflection, to be somewhat flatter (Gamma = 1.75) than that of a typical broad-line Seyfert 1 galaxy. The most obvious feature in the hard X-ray spectrum is a narrow emission line near 6.4 keV with an equivalent width of similar to 50 eV. The energy and strength of this line is consistent with fluorescence from "neutral" iron in the molecular torus, and we note the emerging ubiquity of this feature in XMM-Newton and Chandra observations of Seyfert 1 galaxies over a wide luminosity range. We also find evidence for a second emission line at 6.7-6.9 keV, which we attempt to model by reflection from a highly ionized disk. A "soft excess," evident as an upward curvature in the continuum flux below similar to 1.5 keV, cannot be explained solely by enhanced reflection from the ionized disk. The RGS spectrum shows only weak discrete emission and absorption features in the soft X-ray spectrum, supporting our conclusion that the soft excess emission in Mrk 509 represents the high-energy portion of optically thick, thermal emission from the inner accretion disk.