  We present here a study of chemical abundances in the giant elliptical galaxy
M 87 using high-resolution spectra obtained with the Reflection Grating
Spectrometers during two deep XMM-Newton observations. While we confirm the
two-temperature structure of the inter-stellar medium (ISM) in M 87, we also
show that a continuous temperature distribution describes the data equally
well. The high statistics allows us, for the first time, to determine
relatively accurate abundance values also for carbon and nitrogen. The
comparison of the abundance ratios of C, N, O and Fe in the ISM of M 87 with
those in the stellar population of our Galaxy shows that the relative
contribution of core-collapse supernovae to the enrichment of the ISM in M 87
is significantly less than in the Milky Way and indicates that the enrichment
of the ISM by iron through Type Ia supernovae and by carbon and nitrogen is
occurring in parallel. This suggests that the main source of carbon and
nitrogen in M 87 are the low- and intermediate-mass asymptotic giant branch
stars. From the oxygen to iron abundance ratio in the hot gas we estimate that
the relative number of core collapse and type Ia supernovae contributing to the
enrichment of the ISM in the core of M 87 is ~60% and ~40% respectively. The
spatial distributions of iron and oxygen are different. While the oxygen
abundance distribution is flat the iron abundance peaks in the core and has a
gradient throughout the ~4' wide field of view of the instrument, suggesting an
early enrichment by core-collapse supernovae and a continuous contribution of
type Ia supernovae.

Astrophysics