Galaxies pollute the environments they exist in astronomers have discovered, using a new imaging system to confirm that what flows in is much cleaner than what flows out.
Scientists at the WM Keck Observatory in Hawaii focused on a galaxy called Mrk 1486, about 500 light years away, which is going through a period of rapid star formation.
The heaviest elements in the universe are forged inside the cores of stars through nuclear fusion and, once the stars collapse or explode, these elements spread through the universe.
“Enormous clouds of gas are pulled into galaxies and used in the process of making stars,” explained the co-lead author of the study, Dr 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,” she added, explaining the research published in The Astrophysical Journal.
The mechanisms behind galaxies acquiring more matter (through a process known as accretion), and shed matter (through a process known as outflow) is important to govern their growth, mass, and size.