A team of astronomers at the ARC Center of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D) found that galaxies pollute the environment they exist in. Alex Cameron and Deanne Fisher lead researcher team used a new imaging system, at WM Keck Observatory in Hawaii to confirm that what flows into a galaxy is a lot cleaner than what flows out.
The research paper was published in the Astrophysical journal.
Deanne Fisher, associate professor at the Centre for Astrophysics and Supercomputing at Swinburne University in Australia in an interview said, “Enormous clouds of gas are pulled into galaxies and used in the process of making stars. On its way-in, it is made of hydrogen and helium. By using a new piece of equipment called the Keck Cosmic Web Imager, we were able to confirm that stars made from this fresh gas eventually drive a huge amount of material back out of the system, mainly through supernovas. But this stuff is no longer nice and clean—it contains lots of other elements, including oxygen, carbon, and iron.”
Because of the accretion process of galaxy formation, various gases from the cosmic environment get flooded into this newly forming galaxy and eventually give rise to an explosion. After the explosion, the galaxy starts to takes shape. This accretion process and explosion process of gases are called the inward and outward flow of galaxy formation.
To this date, we were unable to confirm the compositions of inward and outward flow. But now because of this new imaging technology for the first time, we could confirm the full cycle of the galaxy formation other than the Milkyway.
To make their findings, the researchers focused on a galaxy called Mrk 1486, which lies about 500 million light-years from the Sun and is going through a period of very rapid star formation.
“We found there is a very clear structure to how the gases enter and exit,” explained Dr Alex Cameron, who has recently moved from the University of Melbourne in Australia to the UK’s University of Oxford.
“Imagine the galaxy is a spinning frisbee. The gas enters relatively unpolluted from the cosmos outside, around the perimeter, and then condenses to form new stars. When those stars later explode, they push out other gas—now containing these other elements—through the top and bottom.”
The elements—comprising more than half the Periodic Table—are forged deep inside the cores of the stars through nuclear fusion. When the stars collapse or go nova the results are catapulted into the Universe—where they form part of the matrix from which newer stars, planets, asteroids and, in at least one instance, life emerges.
Mrk 1486 was the perfect candidate for observation because it lies “edge-on” to Earth, meaning that the outflowing gas could be easily viewed, and its composition measured. Most galaxies sit at awkward angles for this type of research.
“This work is important for astronomers because for the first time we’ve been able to put limits on the forces that strongly influence how galaxies make stars,” added Professor Fisher.
“It takes us one step closer to understanding how and why galaxies look the way they do—and how long they will last.”
Other scientists contributing to the work are based at the University of Texas at Austin, the University of Maryland at College Park, and the University of California at San Diego plus the Universidad de Concepcion in Chile.