Multi-epoch X-ray observations of the narrow-line Seyfert 1 galaxy SDSS J160508.87+323921.4 with XMM-Newton

We present results of multi-epoch XMM-Newton observations separated by several years of the narrow-line Seyfert 1 (NLS1) galaxy, SDSS J160508.87+323921.4. The NLS1 showed X-ray flux variations on timescales of years as well as low amplitude variations on timescales as short as hours, while the X-ray spectral shape remained essentially unchanged. The spectrum shows a significant soft X-ray excess. The model of reflection from an ionized disc, that is dominant in the whole XMM-Newton bandpass, provides the best description of the observed spectra for all the observations, though alternatives such as Compton scattering (T ∼ 0.25 keV) cannot be ruled out in a statistical sense. For the disc reflection model, the observed variations may originate either from the change in the reflection fraction, or from the variability of the intrinsic X-ray luminosity.