"Not Alien Signals" --FRB's are Pulses from Dark-Matter Stars Captured by Supermassive Black Holes of Early Universe
New research seems to suggest that mysterious fast radio bursts might be stars made of dark matter crashing into black holes, according to Aiichi Iwazaki, an astronomer at Nishogakusha University in Tokyo, who subscribes to the theory that dark matter is made of theoretical particles called axions, very light and long-lived particles that only interact with matter in very weak ways, such as through gravity, the weakest force in the universe. Scientists know dark matter exists based on the observed movements of stars and galaxies throughout the universe, which can only be explained by the gravitational effects of dark matter.
Iwazaki thinks the early universe was small enough for the chances of these particles to clump up into dark matter stars close to the center of galaxies, the habitat of supermassive black holes, where the accretion disk surrounding the black hole would cause axions to decay into photons which may be what astronomers on Earth have observed as the low energy radio wavelengths of FRBs that repeat as random pulses, because the dark matter star blowing through the accretion disk would do so over and over, and irregular intervals, until the star was no longer a compact cluster of axions.
“If there are many axion stars in the centers, we expect that some of them collide with the black hole accretion disc,” says Iwazaki. This mechanism may also explain why some FRBs repeat at irregular intervals, such as FRB 121102, located in a galaxy some 2.5 billion light years away.
In 2015, Iwazaki theorised that FRBs were the product of axion stars hitting the magnetic fields of neutron stars, the ancient remnants of stars several times the sun’s mass. That wouldn’t explain the repetition seen from FRB 121102, because neutron stars don’t have accretion discs that would simply pull material off the axions rather than destroying them.
Joerg Jaeckel at the University of Heidelberg in Germany belives that axions are an attractive hypothesis for dark matter because they address some open questions in particle physics and don’t require a lot of additions to the standard model, the prevailing theory of particle physics that has survived every test so far.