The active nucleus of the ULIRG IRAS F00183-7111 viewed by NuSTAR
  We present an X-ray study of the ultra-luminous infrared galaxy IRAS
F00183-7111 (z=0.327), using data obtained from NuSTAR, Chandra X-ray
Observatory, Suzaku and XMM-Newton. The Chandra imaging shows that a point-like
X-ray source is located at the nucleus of the galaxy at energies above 2 keV.
However, the point source resolves into diffuse emission at lower energies,
extending to the east, where the extranuclear [O III] emission, presumably
induced by a galactic-scale outflow, is present. The nuclear source is detected
by NuSTAR up to the rest-frame 30 keV. The strong, high-ionization Fe K line,
first seen by XMM-Newton, and subsequently by Suzaku and Chandra, is not
detected in the NuSTAR data. The line flux appears to have been declining
continuously between 2003 and 2016, while the continuum emission remained
stable to within 30%. The X-ray continuum below 10 keV is characterised by a
hard spectrum caused by cold absorption of nH ~1e23 cm-2, compatible to that of
the silicate absorption at 9.7 micron, and a broad absorption feature around 8
keV which we attribute to a high-ionization Fe K absorption edge. The latter is
best described by a blueshifted, high-ionization (log xi ~3) absorber. No extra
hard component, which would arise from a Compton-thick source, is seen in the
NuSTAR data. While a pure reflection scenario (with a totally hidden central
source) is viable, direct emission from the central source of L(2-10 keV) =
2e44 erg/s, behind layers of cold and hot absorbing gas may be an alternative
explanation. In this case, the relative X-ray quietness (Lx/L_AGN ~6e-3), the
high-ionization Fe line, strong outflows inferred from various observations,
and other similarities to the well-studied ULIRG/QSO Mrk 231 point that the
central source in this ULIRG might be accreting close to the Eddington limit.
