Astronomers using the South Pole Telescope report that they have discovered the most massive galaxy cluster yet seen at a distance of 7 billion light-years.
Surveying for this effect has significant advantages over other search techniques. It works just as well for very distant clusters as for nearby clusters, which allows astronomers to find very rare, distant, massive clusters. Further, it provides accurate measurements of the masses of these clusters, which are crucial to unravelling the nature of dark energy.
The main goal of the SPT survey is to find a large sample of massive galaxy clusters in order to measure the equation of state of the dark energy, which characterizes cosmic inflation and the accelerated expansion of the universe.
Once this distant cluster was found, the team studied it with the Infrared Array Camera on the Spitzer Space Telescope to pinpoint galaxies within the cluster. Detailed observations of the galaxies' speeds with the Magellan telescopes in Chile proved that the galaxy cluster was a heavyweight.
The team expects to find many more giant galaxy clusters lurking in the distance once the South Pole Telescope survey is completed.
"After many years of effort, these early successes are very exciting. The full SPT survey, to be completed next year, will rewrite the book on the most massive clusters in the early universe," said Brodwin.
Source: Harvard-Smithsonian Center for Astrophysics