London, Dec 20 (IANS): In a first, the observations about the rotating material around massive black holes in the universe reveal that they are "clumpy" rather than smooth as originally thought.

Until recently, telescopes were not able to penetrate some of these thick donut-shaped disks of gas and dust, also known as tori, which feed and nourish the growing black holes tucked inside.

The Monthly Notices of the Royal Astronomical Society study, co-authored by Poshak Gandhi of the University of Southampton, described results from NASA's Nuclear Spectroscopic Telescope Array (NuSTAR) and the European Space Agency's XMM-Newton space observatory.

With its X-ray vision, NuSTAR recently peered inside one of the densest tori known around a supermassive black hole. This black hole lies at the centre of a well-studied spiral galaxy called NGC 1068, located 47 million light-years away in the Cetus constellation.

"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," Gandhi said.

NGC 1068 is well known to astronomers as the first black hole to give birth to the unification idea.

"But it is only with NuSTAR that we now have a direct glimpse of its black hole through such clouds, albeit fleeting, allowing a better test of the unification concept," Andrea Marinucci, of the Roma Tre University in Italy and lead author of the study, said.

The research is important for understanding the growth and evolution of massive black holes and their host galaxies.