The Abundance Pattern in the Hot ISM of NGC 4472: Insights and Anomalies
  Important clues to the chemical and dynamical history of elliptical galaxies
are encoded in the abundances of heavy elements in the X-ray emitting plasma.
We derive the hot ISM abundance pattern in inner and outer regions of NGC 4472
from analysis of Suzaku spectra, supported by analysis of co-spatial XMM-Newton
spectra. The low background and relatively sharp spectral resolution of the
Suzaku XIS detectors, combined with the high luminosity and temperature in NGC
4472, enable us to derive a particularly extensive abundance pattern that
encompasses O, Ne, Mg, Al, Si, S, Ar, Ca, Fe, and Ni in both regions. We apply
simple chemical evolution models to these data, and conclude that the
abundances are best explained by a combination of alpha-element enhanced
stellar mass loss and direct injection of Type Ia supernova (SNIa) ejecta. We
thus confirm the inference, based on optical data, that the stars in elliptical
galaxies have supersolar alpha/Fe ratios, but find that that the present-day
SNIa rate is 4-6 times lower than the standard value. We find SNIa yield sets
that reproduce Ca and Ar, or Ni, but not all three simultaneously. The low
abundance of O relative to Ne and Mg implies that standard core collapse
nucleosynthesis models overproduce O by a factor of 2.
