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Butcher & Oemler Cluster A2111: A Head-on Merger at z = 0.23

Q. Daniel Wang·Melville Ulmer·Russell J. Lavery
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Abstract

We present ROSAT PSPC and HRI observations of A2111, the richest galaxy cluster photometrically surveyed by Butcher & Oemler (1984). The cluster contains a distinct comet-shaped X-ray subcomponent, which appears hotter than the rest of the cluster. The galaxy and X-ray surface brightness distributions of the cluster show a similarly elongated morphology. These results suggest that the cluster is undergoing a head-on subcluster merger. This merger may also be responsible for the high fraction of gas-rich blue galaxies observed in the cluster. We have further detected a poor cluster along the merging axis and at a projected distance of about 5 Mpc from A2111.

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Q. Daniel Wang, Melville Ulmer, Russell J. Lavery. 1997-02-04. Butcher & Oemler Cluster A2111: A Head-on Merger at z = 0.23. https://doi.org/10.1093/mnras%2F288.3.702

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