XMM-Newton observations of the heavily absorbed Seyfert 1 galaxy IC 4329A

Abstract

We detect seven distinct absorbing systems in the high-resolution X-ray spectrum of the Seyfert 1 galaxy IC 4329A, taken with XMM-Newton. Firstly we detect absorption due to cold gas in our own Galaxy and warm gas in the Galactic halo or the Local Group. This local warm gas is only detected through O VII absorption, from which we deduce a temperature between 0.03 and 0.2 keV. In IC 4329A we detect absorption from the host galaxy as well as from a warm absorber, close to the nucleus, which has 4 components. The absorption from the host galaxy is well modeled by neutral material. The warm absorber detected in IC 4329A is photoionized and has an ionization range between log $ξ$ = -1.37 and log $ξ$ = 2.7. A broad excess is measured at the O VIII Ly$α$ and N VII Ly$α$ emission lines, which can be modeled by either disklines or multiple Gaussians. From the lightcurve we find that the source changed luminosity by about 20 % over the 140 ks observation, while the spectral shape, i.e. the softness ratio did not vary. In the EPIC spectra a narrow Fe K$α$ and Fe XXVI Ly$α$ emission line are detected. The narrowness of the Fe K$α$ line and the fact that there is no evidence for flux variability between different observations leads us to conclude that the Fe K$α$ line is formed at a large distance from the central black hole.