A team of astronomers, co-led by Associate Professor Deanne Fisher from the Center for Astrophysics and Supercomputing at the University of Swinburne (Australia) and researcher Alex Cameron from the University of Oxford (England), have used a new imaging system from the WM Observatory Keck in Hawaii to confirm that what flows into a galaxy in the process of star creation is much cleaner than what comes out of it.
Producing stars pollutes the universe
For the study, the astronomers focused on a galaxy called Mrk 1486 that is located about 500 million light years from the Sun. This galaxy represented the perfect source for the observation, since it is located “on the edge of the Earth” , which which means that the gas that comes out can be easily seen and also its composition measured.
This research by the ARC Center of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D) has allowed it to be the first time that the complete cycle has been confirmed in a galaxy other than the Milky Way.
“We found that there is a very clear structure on how gases enter and leave. Imagine that the galaxy is a spinning frisbee. Gas enters relatively uncontaminated from outside the cosmos, around the perimeter, and condenses to form new stars . When those stars later explode, they expel another gas, which now contains these other elements, from the top and bottom, “says Cameron.
And what do they pollute the surroundings with?
“Huge clouds of gas are introduced into galaxies and used in the process of creating stars,” says Fisher. “In its path it is made of hydrogen and helium. By using new equipment called the Keck Cosmic Web Imager, we were able to confirm that stars made from this fresh gas eventually eject a large amount of material out of the system, mainly through supernovae, but this material is no longer nice and clean, it contains many other elements, including oxygen, carbon, and iron. “
The elements found in these ejections, known as “outflows or jets,” comprise more than half of the periodic table of elements and are forged within the nuclei of stars through nuclear fusion. When stars collapse or become novae, what remains is catapulted into the universe, where they form part of the matrix from which new stars, planets, asteroids and, in our case at least, life emerge.
“This work is important to astronomers because for the first time we have been able to put limits on the forces that strongly influence how galaxies form stars,” says Fisher. “It brings us one step closer to understanding how and why galaxies look the way they do and how long they will last.”
Referencia: “The DUVET Survey: Direct Te-based metallicity mapping of metal-enriched outflows and metal-poor inflows in Mrk 1486″ by Alex J. Cameron, Deanne B. Fisher, Daniel McPherson, Glenn G. Kacprzak, Danielle A. Ber5, Alberto Bolatto, John Chisholm, Rodrigo Herrera-Camus, Nikole M. Nielsen, Bronwyn Reichardt Chu, Ryan J. Rickards Vaught, Karin Sandstrom and Michele Trenti, 30 August 2021, The Astrophysical Journal.
DOI: 10.3847/2041-8213/ac18ca
