A space telescope has detected previously unknown ‘cocoons’ of carbon gas, spreading up to 30,000 light years from young galaxies, in a find that could reshape our understanding of how galaxies form.
Researchers believe that the clouds were blasted out of stars by supernova explosions.
No theoretical studies have predicted such huge carbon cocoons around growing galaxies.
It’s the first confirmation that carbon atoms produced inside of stars in the early universe have spread beyond galaxies.
The researchers spotted the mysterious cocoons using the Atacama Large Millimeter/Submillimeter Array (ALMA) to observe galaxies in the early universe.
“We examined the ALMA Science Archive thoroughly and collected all the data that contain radio signals from carbon ions in galaxies in the early Universe, only one billion years after the Big Bang,” says Seiji Fujimoto, the lead author of the research paper who is an astronomer at the University of Copenhagen.
“By combining all the data, we achieved unprecedented sensitivity. To obtain a dataset of the same quality with one observation would take 20 times longer than typical ALMA observations, which is almost impossible to achieve.”
Heavy elements such as carbon and oxygen did not exist in the universe at the time of the Big Bang. They were formed later by nuclear fusion in stars, but it is not yet understood how these elements spread throughout the universe.
The researchers believe the cocoons were blasted into space by supernova explosions.
“Supernova explosions at the final stage of stellar life expel heavy elements formed in the stars,” said Professor Rob Ivison, the director for science at the European Southern Observatory.
“Energetic jets and radiation from supermassive black holes in the centres of the galaxies could also help transport carbon outside of the galaxies and finally to throughout the universe. We are witnessing this ongoing diffusion process, the earliest environmental pollution in the universe.”
The research team noted that, at present, theoretical models are unable to explain such large carbon clouds around young galaxies, probably indicating that some new physical process must be incorporated into cosmological simulations.
“Young galaxies seem to eject an amount of carbon-rich gas far exceeding our expectation,” said Andrea Ferrara, a professor at Scuola Normale Superiore di Pisa.
The team is now using ALMA and other telescopes around the world to further explore the implications of the discovery for galactic outflows and carbon-rich halos around galaxies.