With the help of three NASA observatories, a team of scientists has attempted the near-impossible task of calculating the mass of a ginormous galaxy cluster, formed around 3.8 billion years after the creation of the universe. Situated 10 billion light-years away from Earth, the cluster, named IDCS J1426.5+3508 (or IDCS 1426), has been found to weigh nearly 500 trillion times more than our Sun. According to the researchers, the object, which is as heavy as about 1,000 Milky Ways, could provide valuable information about the formation and evolution of the universe.
Discovered back in 2012 by the Spitzer Space Telescope, the galaxy cluster’s location was estimated with the help of Hawaii-based Keck Observatory and the Hubble Space Telescope. The celestial body’s massive size was predicted using Combined Array for Millimeter Wave Astronomy, while the Chandra X-Ray Observatory confirmed its composition. Containing over 90-percent of dark matter, its presence was determined mainly via its gravitational pull on surrounding standard matter. Speaking about the study, recently published in The Astrophysical Journal, Mark Brodwin, a researcher at the University of Missouri in Kansas City and the leader of the group, said:
We are really pushing the boundaries with this discovery. As one of the earliest massive structures to form in the Universe, this cluster sets a high bar for theories that attempt to explain how clusters and galaxies evolve.
Galaxy clusters are commonly believed to be the largest objects present in the universe, held together solely by means of gravity. IDCS 1426’s great distance from Earth means that the light currently observed by the scientists is actually coming from when the universe was merely 3.8 billion years old. This indicates that the cluster is still in the early part of its lifetime. Given its enormous size, the researchers believe, the cluster must have taken several billion years to form, and is still in the process of evolving.
To calculate the cluster’s weight, the NASA team used three different techniques. First, the astronomers examined its effect on the cosmic microwave background radiation. In the second method, the scientists studied the extent to which light from galaxies further away from IDCS 1426 was scattered by the cluster’s mass. The third approach had the researchers measure the total mass required to confine the X-ray-emitting gas to the object.
Observations from Chandra has revealed the presence of a dense knot of X-rays close to the cluster’s center. According to the scientists, this dense core could have been shifted from the celestial object’s center, possibly by a merger with another cluster some 500 million years earlier. As the team explains, the hot gas present in the surrounding area is symmetric and smooth. This in turn points to IDCS 1426’s rapid formation process. Michael McDonald, the study’s co-author and a researcher at MIT, said:
Mergers with other groups and clusters of galaxies should have been more common so early in the history of the Universe. That appears to have played an important part in this young cluster’s rapid formation.
Despite its rapid growth, however, the cluster seems to contain relatively low quantities of elements heavier than hydrogen and helium, which suggests that it is still in the early stages of evolution. The galaxy cluster might currently be in the process of increasing its hot gas reserve through several supernova explosions. Talking about the research, whose findings were presented at the recent American Astronomical Society meeting, Anthony Gonzalez of the University of Florida in Gainesville, said:
The presence of this massive galaxy cluster in the early Universe doesn’t upset our current understanding of cosmology. It does, however, give us more information to work with as we refine our models.