A&A 401, 443-461 (2003)
DOI: 10.1051/0004-6361:20021791
XMM observation of M 87
II. Abundance structure of the interstellar and intergalactic medium
K. Matsushita, A. Finoguenov and H. BöhringerMax-Planck-Institut für Extraterrestrial Physik, 85748 Garching, Germany
(Received 8 July 2002 / Accepted 22 November 2002)
Abstract
Based on a detailed study of the temperature structure of
the intracluster medium in the halo of M 87, abundance profiles
of 7 elements, O, Mg, Si, S, Ar, Ca, and Fe are derived.
In addition, abundance ratios are derived from the ratios of line
strengths, whose temperature dependences are small
within the temperature range of the ICM of M 87.
The abundances of Si, S, Ar, Ca and Fe show strong decreasing gradients outside
2
' and become nearly constant within the radius at ~1.5 solar.
The Fe/Si ratio is determined to be 0.9 solar with no radial gradient.
In contrast, the O abundance is less than a half of the Si abundance at the
center and has a flatter gradient.
The Mg abundance is ~1 solar within 2
', which is close to stellar
abundance within the same radius.
The O/Si/Fe pattern of M 87 is located at the simple extension of that of Galactic stars.
The observed Mg/O ratio is about 1.25 solar, which is also the same
ratio as for Galactic stars.
The O/Si/Fe ratio indicates that the SN Ia contribution to Si and Fe becomes important
towards the center and SN Ia products have
similar abundances of Si and Fe at least around M 87, which may reflect
dimmer SN Ia observed in old stellar systems.
The S abundance is similar to the Si abundance at the center, but has a
steeper gradient.
This result suggests that the S/Si ratio of SN II products is much
smaller than the solar ratio.
Key words: galaxies: individual: M 87 -- galaxies: intergalactic medium -- galaxies: ISM -- X-rays: galaxies: clusters
Offprint request: K. Matsushita, matusita@xray.mpe.mpg.de
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