  The Seyfert 1.9 galaxy MCG-05-23-016 has been shown to exhibit a complex
X-ray spectrum. This source has moderate X-ray luminosity, hosts a comparably
low-mass black hole, but accretes at a high Eddington rate, and allows us to
study a super massive black hole in an early stage. Three observations of the
INTEGRAL satellite simultaneous with pointed Swift/XRT observations performed
from December 2006 to June 2007 are used in combination with public data from
the INTEGRAL archive to study the variability of the hard X-ray components and
to generate a high-quality spectrum from 1 to 150 keV. The AGN shows little
variability in the hard X-ray spectrum, with some indication of a variation in
the high-energy cut-off energy ranging from 50 keV to >>100 keV, with an
electron plasma temperature in the 10 - 90 keV range. The reflection component
is not evident and, if present, the reflected fraction can be constrained to R
< 0.3 for the combined data set. Comparison to previous observations shows that
the reflection component has to be variable. No variability in the UV and
optical range is observed on a time scale of 1.5 years. The hard X-ray spectrum
of MCG-05-23-016 appears to be stable with the luminosity and underlying power
law varying moderately and the optical/UV flux staying constant. The spectral
energy distribution appears to be similar to that of Galactic black hole
systems, e.g. XTE 1118+480 in the low state. The AGN exhibits a remarkably high
Eddington ratio of L(bol)/L(Edd)> 0.8 (or L(bol)/L(Edd) > 0.1, if we consider a
higher mass of the central engine) and, at the same time, a low cut-off energy
around 70 keV. Objects like MCG-05-23-016 might indicate the early stages of
super massive black holes, in which a strong accretion flow feeds the central
engine.
