Galaxies pump out polluting exhaust gases. Credit: James Josephides, Swinburne Astronomical Productions
Study reveals how star-making pollutes the universe
Researchers have discovered that galaxies pollute the environment in which they reside.
A team of astronomers led by Alex Cameron and Dean Fisher of the ARC Center of Excellence for All 3D Astrophysics (ASTRO 3D) used a new imaging system at the WM Keck Observatory in Hawaii to confirm that what’s flowing into the galaxy is much cleaner than what’s streaming.
The study was published today (August 30, 2021) in Astrophysical Journal.
“Huge clouds of gas are pulled into galaxies and used in the star formation process,” said study co-author Dean Fisher, associate professor at the Center for Astrophysics and Supercomputing at Swinburne University in Australia.
“On the way is made of hydrogen and helium. Using a new instrument, the Keck Cosmic Web Imager, we were able to ensure that stars made of this fresh gas eventually push a huge amount of material out of the system, primarily through supernovae.”
“But these things are no longer pretty and clean – they contain many other elements, including oxygen, carbon and iron.”
The process of flowing atoms into galaxies – known as “accumulation” – and their eventual expulsion – known as “fluxing” – 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 study is the first time the full cycle has been confirmed in another galaxy Milky Way.
To come up with their findings, the researchers focused on a galaxy called Mrk 1486, which is about 500 light-years from the sun and experiences a period of very rapid star formation.
Doctor. “We found that there is a very clear structure of how gases enter and exit,” explained Alex Cameron, who recently moved to the UK from the University of Melbourne in Australia. Oxford university.
“Imagine the galaxy as a spinning Frisbee disk. Relatively unpolluted gas from the surrounding outer universe enters and then condenses to form new stars. When those stars later explode, they push another gas—which now contains these other elements—through the top and bottom.”
The elements – which make up more than half of the periodic table – form deep in the cores of stars by nuclear fusion. When stars collapse or become new, the results occur in the universe—part of the matrix from which the newest stars, planets, and asteroids sprout, and in at least one case, life arises.
Mrk 1486 was the ideal candidate for observation because it is located “at the edge” of the Earth, which means that the flowing gas can be easily seen and its composition measured. Most galaxies fall into awkward corners for these types of searches.
Professor Fisher added: “This work is important to astronomers because for the first time we have been able to establish limits on the forces that strongly influence how galaxies form stars.”
“It brings us one step closer to understanding how and why galaxies look the way they do — and for how long they will last.”
Reference: “DUVET Survey: te-based direct mineral mapping of mineral-rich outflow and mineral–poor outflow in MRk 1486” Aug. 30, 2021, Astrophysical Journal.
DOI: 10.3847 / 2041-8213 / ac18ca
Other contributing scientists work at the University of Texas at Austin, the University of Maryland at College Park and the University of California at San Diego—all in the United States—as well as the University of Concepcion in Chile.
