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

¹ SRON National Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands e-mail: K.C.Steenbrugge@sron.nl
² Kavli Institute for Astrophysics and Cosmology, Stanford University, 382 via Pueblo Mall, Stanford, CA 94305-4060, USA
³ Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking Surrey RH5 6NT, UK
⁴ Physics Department, Technion 32000, Haifa, Israel
⁵ Columbia Astrophysics Laboratory, Columbia University, 550 West 120th street, New York, NY 10027, USA

Received: 28 June 2004
Accepted: 9 November 2004

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  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  Lyα and  Lyα 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 Kα and  Lyα emission line are detected. The narrowness of the Fe Kα line and the fact that there is no evidence for flux variability between different observations leads us to conclude that the Fe Kα line is formed at a large distance from the central black hole.