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A deep Chandra observation of the poor cluster AWM 4 – II. The role of the radio jets in enriching the intracluster medium




We use a Chandra observation of the poor cluster AWM 4 to map the temperature and abundance of the intracluster medium, so as to examine the influence of the central radio galaxy on its environment. While the cluster core is generally enriched to near-solar abundances, we find evidence of supersolar abundances correlated with the radio jets, extending 35 kpc from the core of the central dominant galaxy NGC 6051 along its minor-axis. We conclude that the enriched gas has been transported out of the central galaxy through the action of the radio source. We estimate the excess mass of iron in the entrained gas to be 1.4 × 106 M and find that this can be produced in the core of NGC 6051 within the time-scale of the active galactic nucleus (AGN) outburst. The energy required to transport this gas to its current location is 4.5 × 1057 erg, a significant fraction of the estimated total mechanical energy output of the AGN, though this estimate is dependent on the degree of enrichment of the uplifted gas. The larger near-solar abundance region is also compatible with enrichment by metals mixed outwards from NGC 6051 over a much longer time-scale.