South Pole Telescope hones in on dark energy, neutrinos

Analysis of data from the 10-meter South Pole Telescope is providing new support for the most widely accepted explanation of dark energy — the source of the mysterious force that is responsible for the accelerating expansion of the universe. The results also are beginning to hone in on the masses of neutrinos, the most abundant particles in the universe, which until recently were thought to be without mass. The data strongly support Albert Einstein's cosmological constant —a slight amendment to his theory of general relativity and the leading model for dark energy — even though the analysis was based on only a fraction of the SPT data collected and only 100 of the more than 500 galaxy clusters detected so far. "With the full SPT data set, we will be able to place extremely tight constraints on dark energy and possibly determine the mass of the neutrinos," said Bradford Benson, a postdoctoral scientist at the University of Chicago's Kavli Institute for Cosmological Physics. Benson presented the SPT collaboration's latest findings on April 1 at the American Physical Society meeting in Atlanta. A series of papers detailing the SPT findings have been submitted to the Astrophysical Journal, written by lead authors Benson ; Kavli postdoctoral scientist Ryan Keisler ; and Christian Reichardt , postdoc at the University of California, Berkeley). The results are based on a new method that combines measurements taken by the SPT and X-ray satellites, and extends these measurements to larger distances than previously achieved using galaxy clusters.