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In an article published Monday, researchers at the University of Berkeley refuted existing notions that dark matter is mainly black holes.
The research team consisted of lead author Miguel Zumalacárregui, Marie Curie Global Fellow at the Center for Berkeley's Cosmological Physics, and Professor of Astronomy and Physics on Campus, Uroš Seljak. Zumalacárregui and Seljak have received assistance from supernova experts from the Department of Astronomy on campuses and the Lawrence Berkeley National Laboratory for data analysis, said Zumalacárregui.
According to a press release published by Berkeley News, the composition of dark matter is one of the greatest mysteries of astronomy. Dark matter theoretically accounts for 84.5% of all matter in the universe, but "nobody can find it," according to the press release. Zumalacárregui said that many scientific models suggest that much of this missing material is made up of black holes.
According to Zumalacárregui, he and Seljak have been searching for traces of black holes using supernovae. He added that black holes are invisible and that researchers are looking for their effects on surrounding objects, such as stars. In this case, they investigated the effects of the gravitational lens on type Ia supernovas – tThe same type of supernova proved that the expansion of the universe was accelerating.
"We know how bright supernovas are, so we can compare if there is a black hole between us and the supernova," Zumalacárregui said. "For example, the black hole would act like a lens and magnify the supernova, making it brighter."
The amount of gravitational lenses detected determined that up to 40% of the dark matter could be black holes, which refutes many existing models, Zumalacárregui said. He added that it was "attractive" to believe that much of the dark matter was composed of black holes, but scientists now know that the majority of dark matter is composed of other element.
According to the press release, Zumalacárregui and Seljak used 740 supernovas among the brightest to determine the 40% limit. But since the completion of the research included in the study published Monday, they conducted a "reanalysis" using a more comprehensive list of 1,048 supernovae. Although the reanalysis is not published, the researchers found that the percentage of dark matter that can be black holes is even lower, at about 23% instead of 40%.
Zumalacárregui said the results of his research were "generally enthusiastic and interested" and that this article was "well received". He added that he had received many invitations to present his findings in several departments.
"It's a very interesting study that sets limits of observation on the amount of dark matter that could be made up of primordial black holes," said campus astronomy professor Alex Filippenko. , in an email. "Although there have already been several plausible arguments (some theoretically) against the hypothesis that such black holes make up the bulk of dark matter, this particular research using real data confirms our general skepticism . "
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Yao Huang covers research and ideas. Contact him at [email protected] and follow him on Twitter to @Yhoneplus. "
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