Researchers looked at 170,000 supermassive black holes to test out a decades-old "doughnut theory" on the appearance of black holes.
The 1970s theory worked to explain how black holes had such varied appearance, a NASA Jet Propulsion Laboratory news release reported.
The model suggested every black hole was surrounded by a dusty "doughnut" called a torus, a NASA Jet Propulsion Laboratory news release reported.
The appearance of the black hole would depend on how the torus was situated. This new research suggests there is something other than a doughnut obstructing the view of the black holes.
"Our finding revealed a new feature about active black holes we never knew before, yet the details remain a mystery," Lin Yan of NASA's Infrared Processing and Analysis Center (IPAC), based at the California Institute of Technology in Pasadena, said in the news release. "We hope our work will inspire future studies to better understand these fascinating objects."
Every galaxy has a massive black hole at its center; in this study the researchers focused on ones that feed on surrounding gas.The team used WISE data to look at how both hidden and revealed black holes cluster across the skies.
If every black hole had a similar surrounding doughnut they would all cluster in the same way whether revealed or not; but the team found that more of the hidden black holes were clumped together than the exposed ones.
"The unified theory was proposed to explain the complexity of what astronomers were seeing," Daniel Stern of NASA's Jet Propulsion Laboratory, said in the news release. "It seems that simple model may have been too simple. As Einstein said, models should be made 'as simple as possible, but not simpler.'"
The hidden black holes could have larger dark matter rings.
"The unified theory was proposed to explain the complexity of what astronomers were seeing," Stern said. "It seems that simple model may have been too simple. As Einstein said, models should be made 'as simple as possible, but not simpler.'"
