The study was the first spectral variability survey to study how galaxies change brightness at different frequencies.
Feb 08, 2021 13:29:51 IST
Radio images of the sky have revealed hundreds of “baby” and supermassive black holes in distant galaxies, with the galaxies’ light bouncing around in unexpected ways.
Galaxies are vast cosmic bodies, tens of thousands of light years in size, made up of gas, dust, and stars (like our Sun).
Given their size, you’d expect the amount of light emitted from galaxies would change slowly and steadily, over timescales far beyond a person’s lifetime.
But our research, published in the Monthly Notices of the Royal Astronomical Society, found a surprising population of galaxies whose light changes much more quickly, in just a matter of years.
Missing matter
By Yuanming Wang, University of Sydney and Tara Murphy, University of Sydney
We’ve all looked up at night and admired the brightly shining stars. Beyond making a gorgeous spectacle, measuring that light helps us learn about matter in our galaxy, the Milky Way.
When astronomers add up all the ordinary matter detectable around us (such as in galaxies, stars and planets), they find only half the amount expected to exist, based on predictions. This normal matter is “baryonic”, which means it’s made up of baryon particles such as protons and neutrons.
But about half of this matter in our galaxy is too dark to be detected by even the most powerful telescopes. It takes the form of cold, dark clumps of gas. In this dark gas is the Milky Way’s “missing” baryonic matter.
Thanks to the discovery of five twinkling galaxies in a rare alignment, astronomers have been able to calculate for the first time the properties and geometry of an invisible gas cloud in space.
Radio images of the sky have revealed hundreds of baby and supermassive black holes in distant galaxies, with the galaxies light bouncing around in unexpected ways.