The variable XMM-Newton spectrum of Markarian 766

The narrow-line Seyfert 1 galaxy Mrk 766 was observed for GO ks with the XM M-Newton observatory. The source shows a complex X-ray spectrum. The 2-10 k eV spectrum can be adequately represented by a power law and broad Fe Ka em ission. Between 0.7 and 2 keV the spectrum is harder and exhibits a flux de ficit with respect to the extrapolated medium energy slope. Below 0.7 keV, however, there is a strong excess of emission. The RGS spectrum shows an ed ge-like feature at 0.7 keV; the energy of this feature is inconsistent with that expected for an OVII edge from a warm absorber, Mrk 766 varies by a f actor of similar to2 in overall count rate in the EPIC and RGS instruments on a timescale of a few thousand seconds, while no significant flux changes are observed in the ultraviolet with the Oh I. The X-ray variability is sp ectrally dependent with the largest amplitude variability occurring ill the 0.4-2 keV band. The spectral variability can be explained by a change in f lux and slope of the medium energy continuum emission, superimposed on a le ss variable (or constant) low energy emission component.