Scientific Seminars

10 Billion Years of Galaxy Alignments

Roberto De Propris
University of Turku

2017-03-17    11:00    Brera - Cupola Fiore

The most massive galaxies in clusters today show a strong propensity to share the same orientation as the surrounding matter distribution on large scales. We use Hubble Space Telescope observations of of 60 clusters at 0.2 < z < 1.8 to show, for the first time, that similar alignments are seen at much earlier epochs, when the Universe was only 1/3 of its present age. The alignment, however, is only limited to the first ranked galaxy in each cluster. The brightest cluster galaxies must therefore be the product of a special formation history, related to their position and mass within the cluster, influenced by the development of the cosmic web over billions of years.