A young mammoth cluster of galaxies sighted in the early universe
Astronomers have uncovered evidence for a vast collection of young galaxies 12 billion light years away. The newly discovered "proto-cluster" of galaxies, observed when the universe was only 1.7 billion years old (12% of its present age), is one of the most massive structures known at that distance. The discovery, made using telescopes at Kitt Peak National Observatory in Arizona and the W. M. Keck Observatory on Mauna Kea, has been reported in the Astrophysical Journal.
The team, led by Dr. Lee (Purdue University) and Dr. Arjun Dey of the National Optical Astronomy Observatory, used the Mayall telescope on Kitt Peak to obtain very deep images of a small patch of sky, about the size of two full moons, in the constellation of Bootes. The team then used the Keck II Telescope on Mauna Kea to measure distances to faint galaxies in this patch, which revealed the large grouping. "Many of the faint galaxies in this patch lie at the same distance," say Dr. Dey. "They are clumped together due to gravity and the evidence suggests that the cluster is in the process of forming."
|Coma Cluster image from the Sloan Digital Sky Survey [Credit: Dustin Lang and SDSS Collaboration]|
The team is now searching larger areas of sky to uncover more examples of such young and massive protoclusters. "The discovery and confirmation of one distant and very massive protocluster is very exciting," said Dr. Naveen Reddy, an astrophysicist at the University of California at Riverside and a coauthor of the study, "but it is important to find a large sample of these so we can understand the possibly varied formation history of the population as a whole."
Source: National Optical Astronomy Observatory [May 25, 2016]