XMM-Newton view of X-ray overdensities from nearby galaxy clusters: the
  environmental dependencies
  In this work, we studied ten nearby ($z$$ \leq$0.038) galaxy clusters to
understand possible interactions between hot plasma and member galaxies. A
multi-band source detection was applied to detect point-like structures within
the intra-cluster medium. We examined spectral properties of a total of 391
X-ray point sources within cluster's potential well. Log $N$ - Log $S$ was
studied in the energy range of 2-10 keV to measure X-ray overdensities. Optical
overdensities were also calculated to solve suppression/triggering phenomena
for nearby galaxy clusters. Both X-ray to optical flux/luminosity properties,
($X/O$, $L_{X}$/$L_{B}$, $L_{X}$/$L_{K}$), were investigated for optically
identified member galaxies. X-ray luminosity values of our point sources are
found to be faint (40.08 $\leq$ log($L_{X}$) $\leq$ 42.39 erg s$^{-1}$). The
luminosity range of point sources reveals possible contributions to X-ray
emission from LLAGNs, X-ray Binaries and star formation. We estimated $\sim$ 2
times higher X-ray overdensities from galaxies within galaxy clusters compared
to fields. Our results demonstrate that optical overdensities are much higher
than X-ray overdensities at the cluster's centre, whereas X-ray overdensities
increase through the outskirts of clusters. We conclude that high pressure from
the cluster's centre affects the balance of galaxies and they lose a
significant amount of their fuels; as a result, clustering process quenches
X-ray emission of the member galaxies. We also find evidence that the existence
of X-ray bright sources within cluster environment can be explained by two main
phenomena: contributions from off-nuclear sources and/or AGN triggering caused
by galaxy interactions rather than AGN fuelling.
