IRAS 13197-1627 has them all: Compton-thin absorption, photoionized gas, thermal plasmas and a broad Fe line

Abstract

We report results from the XMM-Newton observation of IRAS 13197-1627, a luminous infrared (IR) galaxy with a Seyfert 1.8 nucleus. The hard X-ray spectrum is steep (Γ ~ 2.5) and is absorbed by Compton-thin (N_H ~ 4 × 10²³ cm^-2) neutral gas. We detect a Fe Kα emission line at 6.4 keV, consistent with transmission through the absorber. The most striking result of our spectral analysis is the detection of a dominant X-ray reflection component and broad Fe line from the inner accretion disc. The reflection-dominated hard X-ray spectrum is confirmed by the strong Compton hump seen in a previous BeppoSAX observation and could be the sign that most of the primary X-rays are radiated from a compact corona (or base of the jet) within a few gravitational radii from the black hole. We also detect a relatively strong absorption line at 6.81 keV which, if interpreted as FeXXV resonant absorption, implies an outflow with velocity ~5 × 10³ km s^-1. In the soft energy band, the high-resolution gratings and the CCD-resolution data show the presence of both photoionized gas and thermal plasma emission, the latter being most likely associated with a recent starburst of 15-20 M_solar yr^-1.

Based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA.

E-mail: miniutti@ast.cam.ac.uk