Impossibly hot object discovered 1.4 billion years after the Big Bang

“We did not expect to see such a hot cluster atmosphere so early in cosmic history.” The oldest and hottest galaxy cluster gas ever recorded could change cosmological models.

An international team of astronomers, led by Canadian researchers, discovered something the universe shouldn’t have: a cluster of galaxies burning with hot gas just 1.4 billion years after the Big Bang — much earlier and at much higher temperatures than theory predicts.

The discovery, presented in an article published on Monday in the journal Naturehe can call into question current models of galaxy cluster formation, which predict that such temperatures only occur in more mature and stable clusters, at a later stage in the life of the universe.

“We did not expect to see a swarm atmosphere so hot, so soon in cosmic history,” he said. Dazhi Zhouresearcher at the University of British Columbia (UBC) and lead author of the study, at UBC.

“In truth, I was skeptical at first in relation to the signal, as it is too strong to be real. But after months of verification, we have confirmed that this gas is at least five times hotter than predictedand even hotter and more energetic than what we find in many current swarms”, adds the researcher.

“This result shows us that something not primordial universeprobably recently discovered in this cluster, was already inject enormous amounts of energy in the surrounding environment and shaping the young swarm, much earlier and more intensely than we thought”, he stated Scott Chapmanprofessor at Dalhousie University and co-author of the study.

Chapman conducted part of the investigation while at the National Research Council of Canada (NRC).

Investigating a ‘baby’ swarm

Going back about 12 billion years, researchers focused on a young cluster of galaxies called SPT2349-56. To do this, the team used the Atacama Large Millimeter / submillimeter Array (ALMA), a network of radio telescopes that includes instruments designed, built and tested by the NRC.

This newly formed swarmwhich is remarkable for its “age”, with a nucleus that extends for about 500 thousand light years — a size comparable to the halo surrounding the Milky Way.

Contains more than 30 active galaxies and forms stars at a speed more than 5,000 times faster than our galaxy, all in a very compact region.

The research team focused on a cosmological instrument called Sunyaev-Zeldovich effectwhich allows scientists to calculate the thermal energy of the intraswarm medium, which gas between galaxies of a given swarm.

“Understanding galaxy clusters is fundamental to understanding the largest galaxies in the universe,” says Chapman. “These massive galaxies live mainly in clusters and their evolution is strongly shaped by the intense environment of the clusters during formation, including the intracluster environment.”

Current models suggest that the enormous reservoirs of gas that form the intracluster medium are brought together and then heated by gravitational interactions as the swarm, initially immature and unstable, matures and collapses until reaching a stable state.

The discovery suggests that the birth of these swarms is more explosive than previously thought, and that scientists may have to rethink the sequence and speed of evolution of galaxy clusters.

Researchers now want to understand how all these pieces fit together. “We want to understand how intense star formation, active black holes and this superheated atmosphere interact, and what this tells us about the formation of current galaxy clusters,” said Zhou. “How is it possible that all this is happening at the same time, in such a young and compact system?”