Astronomers have discovered that galaxies pollute their environment, and the team used a new imaging system to confirm that what flows into the galaxy is much cleaner than what flows out.
Co-lead author Dean Fisher, a professor at the Center for Astrophysics and Supercomputing at Swinburne University in Australia, said: ‘Massive clouds of gas are pulled into galaxies and used in the star-forming process, and on their way in are made of hydrogen and helium. Using a new piece of equipment called Keck Cosmic Web Imager, we were able to confirm that stars made of this fresh gas eventually push a huge amount of material out of the system, mainly through supernovae.But this material is no longer pure, it contains a lot of other elements, including Including oxygen, carbon and iron.
The process of flowing atoms into galaxies, known as ‘accumulation’, and their eventual expulsion, known as ‘outflows’, is an important mechanism that controls the growth, mass and size of galaxies.
So far, however, the composition of the internal and external flows can only be guessed at. This research is the first time that the full cycle has been confirmed in a galaxy other than the Milky Way.
To achieve their findings, the astronomers focused on a galaxy called Mrk 1486, which is located about 500 million light-years from the sun and is undergoing a period of very rapid star formation.
Dr Alex Cameron, who recently moved from the University of Melbourne in Australia to the University of Oxford, said: “We found that there is a very clear structure of how gases enter and exit.”
He continued, “Imagine that the galaxy is a rotating compact disk. Relatively unpolluted gas from the outer universe enters, around the ocean, and then condenses to form new stars. When these stars explode later, they push out another gas, which contains other elements.”
Each different chemical element has a specific set of light colors, or wavelengths, that it emits which are referred to as emission lines.
“If we measure the relative brightness of different emission lines from different elements such as oxygen and hydrogen, this allows us to determine the chemical composition of the gas,” says Cameron.
KCWI can do this in different regions of the galaxy at the same time, allowing scientists to measure the chemical composition of the flowing gas.
They focused on Mrk 1486 as undergoing high rates of star formation.
The gas enters the galaxy relatively unpolluted around the ocean and condenses to form new stars. After those stars live their lives and explode, they push another gas, now containing heavier elements, in the supernova explosion, through the top and bottom of the galaxy, according to the scientists.
The new study is helping astronomers understand how galaxies, including the Milky Way, form and evolve over time.
“In the early universe, before the first galaxies formed, hydrogen and helium were basically the only elements present,” Cameron says. “The elements that make up the rest of the periodic table of elements were made by stars, which formed inside galaxies.”
When stars create these new elements, some of them can be recycled by their host galaxies and turned into new stars, according to rt.
However, scientists were not sure how much of these elements is retained by the galaxy, and how much of it is being expelled from the galaxy?
Cameron explained: “We know that in the present-day Milky Way there are a number of these elements heavier than in the very early universe. Measuring the elements in the inflows and outflows of galaxies helps us understand what might have happened during the history of the galaxy as it has grown over time. to the galaxy as it is today.”