Research Reveals How Star-Making Pollutes the Cosmos
Galaxies pollute the environment they exist in, researchers have found.
A team of astronomers led by Alex Cameron and Deanne Fisher from the ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D) used a new imaging system on at the WM Keck Observatory in Hawaii to confirm that what flows into a galaxy is a lot cleaner than what flows out.
The research is published today (August 30, 2021) in The Astrophysical Journal.
“Enormous clouds of gas are pulled into galaxies and used in the process of making stars,” said co-lead author Deanne Fisher, associate professor at the Centre for Astrophysics and Supercomputing at Swinburne University in Australia.
“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.”
The process of atoms flooding into galaxies – known as ‘accretion’ – and their eventual expulsion – known as ‘outflows’ – is an important mechanism governing the growth, mass, and size of galaxies.
Until now, however, the composition of the inward and outward flows could only be guessed at. This research is the first time the full cycle has been confirmed in a galaxy other than the