  Recent XMM-Newton observations have measured the hard (2.5-12 keV) X-ray
spectrum of the well-known Seyfert galaxy NGC 4151 with a signal-to-noise
unprecedented for this source. We find that a spectral model, developed to fit
previous Beppo-SAX and ASCA observations of NGC 4151, provides an excellent
description of the XMM-Newton EPIC data. The results support the view that it
is the level of the continuum that is the main driver of the complex spectral
variability exhibited by NGC 4151. We focus on the iron K features in the NGC
4151 spectrum. There is no requirement for a relativistically broadened iron Ka
line, in contrast to several earlier studies. The iron Ka line profile is well
modelled by a narrow Gaussian, the intensity of which varies by ~25% on
timescales of about a year. There is also a strong suggestion that the cold
media present in the active nucleus of NGC 4151 have an iron abundance that is
at least twice the solar value.

Astrophysics