Australian National University’s (ANU) associate Professor Roland Crocker co-authored the study that made the discovery, which crucially ruled out a rival hypothesis that believed the huge light was caused by dark matter particles destructively colliding.
“This is significant because dark matter researchers have long believed an observation of gamma rays from a dwarf satellite would be a strong indicator of dark matter — this study shows otherwise, but we’re still looking for those dark matter signatures,” said Professor Crocker.
The puzzling light-filled “cocoon” or “fermi bubbles” have been on the minds of astronomers since their discovery in 2012, and new information from ANU about gamma rays solves part of its mystery.
Fermi bubbles, previously thought to be the result of dark matter, can now be resolved as gamma rays being emitted from millisecond pulsars.
These fermi bubbles, the focus of this study, also known as huge globe-like formations sitting about 50,000 lightyears away from Earth, have been producing a particularly bright light.
“One of the brightest spots, the fermi cocoon, is found in the southern bubble,” Professor Crocker said.
This light was originally thought to be the result of a past outburst from the Galaxy’s monster of a black hole.
Now the new studies show that it is in fact coming from a neighboring dwarf galaxy, Sagittarius.
The Sagittarius dwarf galaxy has since lost almost all of its interstellar gas and stars due to the strong gravitational pull of the Milky Way; meaning that the gamma radiation can only be explained by a population of millisecond pulsars or extremely rapidly spinning stars.
Gamma rays are thankfully blocked by the Earth’s atmosphere but this hidden view of these particles of light meant that scientists had no clue the extend of its power.
It wasn’t until instruments were sent into space that these discoveries could be made.
This newest discovery offers astronomers a new set of clues about the everyday going about of millisecond pulsars that was previously unknown.
“Our findings suggest millisecond pulsars are an important source of gamma rays in inactive galaxies like Sagittarius. Similar processes could be going on in other dwarf satellite galaxies of the Milky Way,” associate Professor Crocker commented.
While the mystery of the illuminating cocoons becomes solved, the mysteries surrounding the search for dark matter is still very much at large.
Adam is a journalist who has worked for more than 40 prestigious media brands in the UK and Australia. Since 2005, his varied career has included stints as a reporter, copy editor, feature writer and editor for publications as diverse as Fleet Street newspaper The Sunday Times, fashion bible Jones, media and marketing website Mumbrella as well as lifestyle magazines such as GQ, Woman’s Weekly, Men’s Health and Loaded. He joined Momentum Media in early 2020 and currently writes for Australian Aviation and World of Aviation.
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