A team of astronomers had detected the most distant galactic wind observed to date, corresponding to a time when the Universe was only 1,000 million years old, reported the ALMA observatory team. By watching the flow of hydroxyl molecules, which reveal the presence of gas from which stars form, the researchers explained how a “star-birth frenzy” impacted some galaxies in the early Universe.
According to the authors of the study, published in the journal Science, to avoid being consumed quickly in a dramatic flare, some galaxies “shut down” the process of star formation by ejecting, at least temporarily, large amounts of gas. The gas either disperses entirely or flows slowly back into the galaxy to feed new outbreaks of star formation processes.
Until now, astronomers had been unable to directly observe these powerful jets in the early days of the early Universe, where these mechanisms were essential to prevent galaxies from growing too fast and too much.
“Galaxies are complicated and chaotic monsters, and we believe that these jets and galactic winds are fundamental elements of their formation and evolution processes that regulate their ability to grow,” says Justin Spilker, an astronomer at the University of Texas.
Galactic winds are the mechanisms the galaxies “use” to limit their growth and star birth
For astronomers, “this finding provides new information on how some galaxies in the early Universe self-regulated their growth to continue making stars later.”
Astronomers observed galactic winds of the same size, speed and mass as the newly discovered one in nearby galaxies with star-forming incubators, but the jet seen with the help of ALMA is the most distant one observed to date. The galaxy, known as SPT2319-55, is more than 12 billion light years from Earth and was discovered by the South Pole Telescope of the US National Science Foundation.
The scientists even pointed out that the strong galactic wind of the gas that forms stars leaves the galaxy at almost 800 kilometers per second.
“It is not a gentle, constant breeze, but isolated eruptions that expel gas at the same rate at which it would be transformed into new stars,” the authors point out. From now on, we can also “determine the wind speed and get an approximate idea of the amount of material contained in the jet,” explains Spilker.
According to the researchers, molecular galactic winds are an efficient mechanism for galaxies to self-regulate their growth.