With the recent Dark Matter Ring, if you were to look at that structure from the side I think the upper and lower parts of the ring would look very similar. In that situation the dark matter had been 'splashed' out of the central region dominated by the galaxy clusters, as they passed through each other.

In Abell520 we may be seeing the same thing except side on, if the galaxy clusters are colliding perpendicular to our line of sight.

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plenty of woo, at the hotel hoagaland...