Galaxies are big polluters, new research

The galaxies pollute the environment they found in astronomers and use a new imaging system to ensure that what flows in is much cleaner than what flows out.

Scientists at the WM-Keck Observatory in Hawaii focused on a galaxy about 500 light-years away called Mrk 1486, which is going through a phase of rapid star formation.

The heaviest elements in the universe are forged in the cores of stars through nuclear fusion, and as soon as stars collapse or explode, these elements spread throughout the universe.

“Huge clouds of gas are drawn into the galaxy and used in star formation,” said the study’s lead author, Dr. Deanne Fisher, Associate Professor in the Center for Astrophysics and Supercomputers at Swinburne University in Australia.

“All the way, it was made up of hydrogen and helium. Using a new device called the Keck Cosmic Web Imager, we were able to confirm that this star made of fresh gas would eventually consist of a large amount of material, mainly from supernovae.

“But this stuff is no longer nice and clean – it contains a lot of other elements, including oxygen, carbon, and iron,” he added, explaining the research published in the Astrophysical Journal.

The mechanisms behind galaxies, which accept more matter (through a process known as accretion) and reject matter (through a process known as outflow), are important in determining their growth, mass, and size.

As the researchers explain, if one imagines the galaxy as a spinning Frisbee, then gas and matter penetrates “relatively unpolluted” from the cosmos beyond.

It comes around it, follows the rotation of the galaxy, creates an accretion disk, and condenses to form new stars.

When these stars then explode, they push the gas and other matter, which now contains all of this new element, through the top and bottom of this frisbee.

But until now scientists have not been able to observe the composition of the flow of matter into and out of galaxies other than the Milky Way.

Mrk 1486 is a “perfect candidate” for this observation because it is “rand-on” to Earth, meaning that the escaping gas can be easily observed and its composition measured. Most galaxies sit in awkward corners for this type of research.

“This work is important to astronomers because, for the first time, we were able to constrain the forces that strongly influence how galaxies form stars,” added Prof Fisher.

“This brings us one step closer to understanding how and why galaxies look the way they do — and how long they last,” he added.

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