Galactic gas: A bump in the radio road<\/p>\n
When you think about the shape of a galaxy, most of us can imagine the Milky Way and its spinning disc of stars.<\/p>\n
But where a galaxy ends, theres still a lot of material surrounding it an area referred to as the galactic halo.<\/p>\n
Astronomers have been studying these haloes over the years with the hope of learning more about the life cycle of galaxies.<\/p>\n
A group of physicists have discovered something unusual about the galactic halo, and it could be a piece in the puzzle of why galaxies stop growing.<\/p>\n
Image|J. Josephides, Centre for Astrophysics and Supercomputing, Swinburne University of Technology. <\/p>\n
An artists impression of Fast Radio Burst 181112 travelling through the halo of a galaxy 4 billion light-years from Earth.<\/p>\n
To explain what was found by this multinational team of astrophysicists, we first need to talk about fast radio bursts (FRBs).<\/p>\n
FRBs are powerful flashes of energy from deep space that appear for mere milliseconds in our night sky.<\/p>\n
Depending on what these bursts pass through as you can see in the video below the light can arrive distorted in a variety of ways.<\/p>\n
In November 2018, an FRB was detected that had passed through a galaxy 4 billion light years away.<\/p>\n
This burst was picked up by the Australian Square Kilometre Array Pathfinder (ASKAP) radio telescope in outback Western Australia.<\/p>\n
When this burst passed through the galaxy, researchers expected the wild and stormy gases in its galactic halo would distort the signal.<\/p>\n
What they found instead was a tranquil sea of gas surrounding the galaxy.<\/p>\n
Video|CSIRO\/ICRAR\/OzGrav\/Swinburne University of Technology. <\/p>\n
A fast radio burst leaves a distant galaxy, travelling to Earth over billions of years and occasionally passing through clouds of gas in its path<\/p>\n
Galactic haloes have always been difficult to study, according to astrophysicist Associate Professor Jean-Pierre Macquart.<\/p>\n
The halo of gas can actually extend out 10 times further than the stars in a galaxy and can contain a substantial amount of the matter thats in a galaxy, he says.<\/p>\n
But its very difficult to see the gas directly with a telescope.<\/p>\n
Jean-Pierre is from the Curtin University node of the International Centre for Radio Astronomy Research (ICRAR), which manages ASKAP, and is a co-author of the study.<\/p>\n
The study brought together astronomers from around the world with researchers from Australia, Japan, Korea, America and Chile.<\/p>\n
He says the research team looked at how a single FRB distorted as it travelled 5 billion light years through the universe.<\/p>\n
They believed the signal would be distorted by the galactic halo, much in the same way heat can cause air to shimmer.<\/p>\n
Thats what we thought would happen that the signal from the fast radio burst would be completely distorted after passing through the hot atmosphere of the galaxy, says Jean-Pierre.<\/p>\n
But instead of the stormy galactic weather we were expecting, the pulse we observed had travelled through a calm sea of unperturbed gas.<\/p>\n
It means these gas haloes could be a lot less turbulent than astronomers thought, with less density and magnetisation.<\/p>\n
Image|OzGrav, Swinburne University of Technology. <\/p>\n
An artists impression of fast radio bursts (FRBs).<\/p>\n
University of California Professor of Astronomy and Astrophysics J. Xavier Prochaska led the research and says halo gas has a similar use to fossil records only on a galactic scale.<\/p>\n
Our observations can inform theories about how matter is ejected and how magnetic fields are transported from the galaxy, he says.<\/p>\n
Our research appears to reveal something entirely new about galactic haloes.<\/p>\n
Unless of course, this galaxy happens to be just some weird exception and with only one object, you cant be sure about that.<\/p>\n
Finding another FRB which has travelled through a galaxys halo is the next big test.<\/p>\n
And if we find the same results, it could help us figure out why galaxies suddenly stop growing.<\/p>\n
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Continued here:<\/p>\n
Galactic gas: A bump in the radio road - Particle<\/a><\/p>\n","protected":false},"excerpt":{"rendered":" Galactic gas: A bump in the radio road When you think about the shape of a galaxy, most of us can imagine the Milky Way and its spinning disc of stars. But where a galaxy ends, theres still a lot of material surrounding it an area referred to as the galactic halo Continue reading