EDP Sciences
Free Access
Volume 401, Number 2, April II 2003
Page(s) 443 - 461
Section Extragalactic astronomy
DOI https://doi.org/10.1051/0004-6361:20021791

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. Böhringer

Max-Planck-Institut für Extraterrestrial Physik, 85748 Garching, Germany
(Received 8 July 2002 / Accepted 22 November 2002)

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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