A team of astronomers has discovered the most distant cluster of red galaxies ever observed using FourStar, a new and powerful near-infrared camera on the 6.5-metre Magellan Baade Telescope.
The galaxy cluster is located 10.5 billion light-years away in the direction of the constellation Leo. It is made up of 30 galaxies packed closely together, forming the earliest known “galaxy city” in the universe. The findings will be published in the Astrophysical Journal Letters.
Remarkably, the cluster was completely missed by previous surveys, which searched this region of the sky for thousands of hours and were conducted by all the major ground- and space-based observing facilities, including the Hubble Space Telescope. Despite these intense observations, accurate distances for such faint and distant galaxies were missing until the advent of FourStar.
Eric Persson of the Carnegie Observatories led the development of the new camera that enabled these observations.
Persson and his team equipped FourStar with five special filters to collect images that are sensitive to narrow slices of the near-infrared spectrum, says a Carnegie Institution for Science in Washington, DC press release. This powerful approach allows them to measure accurate distances between Earth and thousands of distant galaxies at one time, providing a 3-D map of the early universe.
The 3-D map revealed the conspicuous concentration of galaxies that existed when the universe was only three billion years old.