Many of space's massive black holes are surrounded by donut-shaped disks called tori, which are made up of dust and gas. Past telescopes failed to penetrate these cosmic donuts.
A research, jointly conducted by the U.S. space agency NASA and the European Space Agency (ESA), found these space donuts are lumpier than previously thought. Scientists previously thought they were simple, rounded disks but latest research showed they look more like lumpy, defective donuts.
NASA's Nuclear Spectroscopic Telescope Array (NuSTAR) succeeded in penetrating one of the space's most dense tori. The accompanying supermassive black hole is located in the middle of NGC 1068 spiral galaxy, which lies 47 million light years from the constellation Cetus.
Latest observations found the rotating disc is lumpier, just like defective donuts thrown away by pastry shops. Regardless of its imperfection, the research recorded for the first time the toris' clumpy nature and supported the theory of the phenomenon's common occurrence.
Findings are crucial in better understanding host galaxies and how massive black holes grow and evolve. The research was published in the journal Monthly Notices Letters of the Royal Astronomical Society on Dec. 17.
"We don't fully understand why some supermassive black holes are so heavily obscured, or why the surrounding material is clumpy. This is a subject of hot research," said co-author Dr. Poshak Gandhi from the University of Southampton.
Both ESA's XMM-Newton and NASA's NuSTAR analyzed NGC 1068's supermassive black hole twice between 2014 and 2015. NuSTAR observed a brightness spike in August 2014 wherein there was a clearing in the material's thickness, said the scientists.
"It's like a cloudy day, when the clouds partially move away from the sun to let more light shine through," said lead author Andrea Marinucci from Italy's Roma Tre University.
Toris around gigantic black holes were first raised in mid-1980s. The donuts aim to explain why some black holes lie hidden in a disk of dust and gas, whiles others lie bare. The donuts' orientation affects how scientists detect the black holes and its corresponding radiation from Earth.
If the donut can be seen from Earth edge-on, it suggests that the black hole is blocked. When the donut can be seen face-on, scientists can detect the black hole and its surrounding materials. The scientific community calls it the unified model, which brings together various black hole types by looking at their donut orientation.
NGC 1068's supermassive black hole gave birth to the unified model idea. But it is only now that the scientific community was able to get a direct sight of the black hole through the thick clouds using NuSTAR.
Future studies will analyze the cause of the toris' clumpy nature. Theories are being drawn, one of which is that black holes could be generating turbulence as they eat up surrounding materials.
