Ten Billion Years of Brightest Cluster Galaxy Alignments

Understand

A galaxy's orientation is one of its most basic observable properties.

• Astronomers once assumed that galaxies are randomly oriented in space, however it is now clear that some have preferred orientations with respect to their surroundings.
• Chief among these are giant elliptical galaxies found in the centers of rich galaxy clusters.
• Numerous studies have shown that the major axes of these galaxies often share the same orientation as the surrounding matter distribution on larger scales.