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Role of disk galaxies in the chemical enrichment of the intracluster medium
B.M. Shustov and
Received 27 July 1998 / Accepted 14 January 1999
Elliptical galaxies are often assumed to be the primary source of heavy elements in the intracluster medium (ICM), with the contribution of other morphological types being negligible. In this paper we argue that a role of spiral galaxies in the chemical evolution of the ICM is also important. This statement rests upon our recent calculations of the heavy element loss from a disk galaxy through the hot steady-state galactic wind and dust grains expulsion by stellar radiation pressure. This model reproduces main properties of our Galaxy and, being applied to galaxies of various masses, explains the observed correlation between spiral galaxy mass (luminosity) and metallicity. In our model this correlation develops as a result of the mass dependence of both loss mechanisms, in the sense that less massive galaxies lose metals more efficiently. We show that a typical disk galaxy is nearly as effective in enriching the ICM as an elliptical galaxy of the same mass.
Having estimated the oxygen and iron loss from a single galaxy, we integrate them over the galactic mass spectrum. We show that the `effective' loss (per unit luminosity) from spiral galaxies is comparable to the loss from ellipticals. The dominant role of early-type galaxies in rich clusters is caused by that they outnumber spirals. We present some arguments to this point, based on recent determinations of the ICM abundances, emphasizing the fact that the ratio of total iron mass to cluster luminosity does not depend on the fraction of cluster spirals in a wide range of the latter, contrary to what one might expect if spirals do not contribute into the ICM Z-abundance.
Key words: galaxies: clusters: general galaxies: evolution galaxies: intergalactic medium galaxies: spiral
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Online publication: April 12, 1999