Universe relic: Huge bubble within a web of galaxies found

These waves emerged as areas of somewhat higher density began to collapse under the influence of gravitational forces while the extreme radiation emitted by the cosmic explosion (Big Bang) attempted to disperse the surrounding matter. This conflict between gravity and radiation caused the plasma to create ripples that propagated outward.

As the universe expanded and cooled, these waves were frozen in time, forming a massive bubble-like structure, while comic entities, like galaxy clusters, formed along them over eons. 

Astronomers hunt for the signature of these time-frozen waves to independently determine the rate of universe expansion. 

Coming to this remarkable new development, the University of Hawaii scientists unexpectedly discovered one such enormous bubble among a web of galaxies about 820 million light years beyond Earth.

The official release describes it as a “fossil-like remnant of the birth of the universe.” 

“We were not looking for it. It is so huge that it spills to the edges of the sector of the sky that we were analyzing. As an enhancement in the density of galaxies, it is a much stronger feature than expected. The very large diameter of one billion light years is beyond theoretical expectations. If its formation and evolution are in accordance with theory [Big Bang], this BAO is closer than anticipated, implying a high value for the expansion rate of the universe,” explained Brent Tully, an astronomer from the university, in the release.

And they've named this cosmic bubble "Hooleilana," which comes from the Kumulipo, a Hawaiian creation chant. 

How this massive bubble was located?

However, finding these massive bubbles in the vast universe is difficult. Astronomers believe this could be the first-ever documented evidence linked to a BAO. 

The bubble came into the spotlight while scourging through a large dataset called Cosmicflows-4, a compilation of precise distances to galaxies. 

This discovery might help scientists better grasp how galaxy evolution affects the universe at large. 

Furthermore, comprehending the structure of the bubble could unravel a great deal of information about the properties of these "ancient messengers." And in turn, could solve various enigmas about the early universe. 

“Mapping Hoʻoleilana in three dimensions helps us understand its content and relationship with its surroundings,” said Daniel Pomarede, a researcher at the CEA Paris-Saclay University in France.

The bubble includes various well-known clusters  

While conducting this study, the team found that in a 2016 research paper, Hoʻoleilana had been mentioned as the most notable among several shell-like structures observed in the Sloan Digital Sky Survey. Nevertheless, the previous study did not provide a complete understanding of its structure and did not conclude that they had identified a BAO.

By utilizing data from the Cosmicflows-4 catalog, this study provided a comprehensive analysis of a spherical shell of galaxies and the bubble’s central region.

This bubble encompasses several prominent structures previously identified by astronomers, including the Harvard/Smithsonian Great Wall, which houses the Coma Cluster, the Hercules Cluster, and the Sloan Great Wall. While at its heart lies the Boötes Supercluster. 

“In detail, Hoʻoleilana is slightly larger than anticipated from the theory of the standard model of cosmology, and what has been found from prior statistical pairwise studies of galaxy separations. The size is in accord with observations of the local expansion rate of the universe and of galaxy flows on large scales that also hint at subtle problems with the standard model,” concluded the statement. 

The study has been reported in the Astrophysical Journal. 

Study abstract:

Theory of the physics of the early hot universe leads to a prediction of baryon acoustic oscillations (BAOs) that has received confirmation from the pairwise separations of galaxies in samples of hundreds of thousands of objects. Evidence is presented here for the discovery of a remarkably strong individual contribution to the BAO signal at z = 0.068, an entity that is given the name Ho'oleilana. The radius of the 3D structure is  Mpc. At its core is the Boötes supercluster. The Sloan Great Wall, Center for Astrophysics Great Wall, and Hercules complex all lie within the BAO shell. The interpretation of Ho'oleilana as a BAO structure with our preferred analysis implies a value of the Hubble constant.