Voids have a bright side

A new study, examining how galaxy images should appear distorted in the Universe, has been published by a team including ACGC researchers: "Antilensing: the Bright Side of Voids", Krzysztof Bolejko, Chris Clarkson, Roy Maartens, David Bacon, Nikolai Meures, and Emma Beynon, Phys. Rev. Lett. 110, 021302 (2013).

Usually, the large voids in the Universe are expected to cause the images of background galaxies to appear smaller and less bright, due to the gravitational bending of light known as gravitational lensing. But our team finds that this can be completely overcome by another effect, so that galaxies behind the void will appear brighter and larger than usual: this is due to the void expanding faster than the surrounding Universe, leading to an overestimate of the distance to these objects.

The paper is highlighted in Physics , Science , and Inside Science.