Astronomers find the biggest galaxy cluster from when the universe was half its present age.
Three new observatories are mining the microwave background radiation from the Big Bang to pinpoint galaxy clusters.
The new technique should provide evidence to support or refute current theories of how the universe evolved.
Astronomers on the hunt for the biggest, most distant gangs of galaxies have landed a prize catch, a behemoth of a cluster 800 trillion times more massive than the sun ferreted out by a new cosmic fishing net from when the universe was half its present age.
The galaxy cluster, known as SPT-CL J0546-5345, is so far away that its glow takes 7 billion light-years to reach us.
Astronomers like these oddball giants because they show what happens in the most richly dense parts of the universe. That information interests cosmologists trying to work out how the universe came to exist and the role of dark energy in fueling its growth, as well as to observational astronomers studying how galaxies formed.
Credit for the catch goes to the South Pole Telescope, one of three observatories designed to detect distortions in the ubiquitous shimmer of radiation emanating from the Big Bang creation event. The telescopes sift through the background cosmic radiation to find spots where it has been slightly perturbed as it passes through extremely hot gas, a hallmark characteristic of galaxy clusters.
“The cosmic microwave background has been our most important source of information about the geometry and contents of the universe,” astronomer Charles Lawrence, with NASA’s Jet Propulsion Laboratory in Pasadena, Calif., told Discovery News.
X-ray telescopes can detect this gas, but finding targets has been a hit-or-miss proposition. Sky surveys under way by the South Pole Telescope, the Atacama Cosmology Telescope in Chile and the Planck space observatory, all of which mine the cosmic background rays, are changing the paradigm.
The discovery of SPT-CL J0546-5345 and its confirmation as the most massive galaxy cluster ever found at 7 billion light-years — a time/distance boundary known in scientific parlance as “redshift 1” — shows that these new types of surveys are successful, says astronomer Mark Brodwin, with the Harvard-Smithsonian Center for Astrophysics.
“Really massive clusters are really, really rare, so you have to cover a lot of area of the sky if you want to find some,” Brodwin told Discovery News. “These surveys are really working, they really find clusters above redshift of one, and they find super interesting clusters. We’ve never found something this massive before.”
In studies of galaxies, size matters.