Giant primordial black holes ruled out as dark matter
Published
Physicists have crossed another dark matter candidate off the list. According to Universe Today, a new Physical Review Letters paper, "Closing the Mass Window for Stupendously Large Black Holes", finds that so-called SLABs cannot make up dark matter.
SLABs are hypothetical primordial black holes with masses from about 100 million up to 10 billion billion times that of the Sun. If they formed from dense patches of matter shortly after the Big Bang, they should have left an imprint on the cosmic microwave background, the oldest light we can detect, released when the Universe was about 380,000 years old.
The team, led by Christopher Gerlach of Johannes Gutenberg University Mainz, searched data from ESA's Planck satellite and found no such signs. Planck ended its mission in 2013, but better computing, new data to cross-check against and improved ways of filtering out Milky Way interference still give new results from it. Gerlach said the continued findings show how important the satellite was.
Note what this does and does not say: it removes one heavy-black-hole option, while other candidates such as WIMPs and axions remain open. The article describes dark matter as a possible answer by elimination.
Which candidate do you think will be the last one standing?