A metal-rich elongated structure in the core of the group NGC4325
  We used X-ray 2D spectrally resolved maps to resolve structure in temperature
and metal abundance. To perform stellar population analysis we applied the
spectral fitting technique with STARLIGHT to the optical spectrum of the
central galaxy. We simulated the chemical evolution of the central galaxy.
While the temperature, pseudo-pressure, and pseudo-entropy maps showed no
inhomogeneities, the iron spatial distribution shows a filamentary structure in
the core of this group, which is spatially correlated with the central galaxy,
suggesting a connection between the two. The analysis of the optical spectrum
of the central galaxy showed no contribution by any recent AGN activity. Using
the star formation history as input to chemical evolution models, we predicted
the iron and oxygen mass released by supernovae (SNe) winds in the central
galaxy up to the present time. Comparing the predicted amount of mass released
by the NGC4325 galaxy to the ones derived through X-ray analysis we conclude
that the winds from the central galaxy alone play a minor role in the IGM metal
enrichment of this group inside r2500. The SNe winds are responsible for no
more than 3% of it and of the iron mass and 21% of the oxygen mass enclosed
within r2500. Our results suggest that oxygen has been produced in the early
stages of the group formation, becoming well mixed and leading to an almost
flat profile. Instead, the iron distribution is centrally peaked, indicating
that this element is still being added to the IGM specifically in the core by
the SNIa. A possible scenario to explain the elongated iron-rich structure in
the core of the NGC4325 is a past AGN activity, in which our results suggest an
episode older than ~10^7-10^8 yrs and younger than 5x10^8.
