Giant Black Hole Reveals Cool, Dusty Surprise in Active Galaxy

In the center of an active galaxy, a huge black hole consumes matter from its surroundings. Now, ESO's Very Large Telescope Interferometer has gathered the most detailed observations ever of the space dust around this massive black hole, revealing unprecedented details about the dust and showing scientists a little more about how black holes behave.

Black holes are actually more common than you might think. Over the last twenty years, astronomers have found that almost all galaxies have a black hole at their center. While some of these black holes grow as they greedily gobble down gases in their vicinity, others are dormant. The ones that are active, though, can create the most energetic objects in the universe: active galactic nuclei (AGN). The middle of these galactic powerhouses are ringed by doughnuts of cosmic dust, dragged from their surroundings--think of the whirlpool in your tub as the water goes down the drain.

Now, scientists have another view of these cosmic doughnuts. They observed a nearby active galaxy called NGC 3783 and found that its doughnut-shaped torus, which burns between 700 to 1,000 degrees Celsius, also had huge amounts of cooler dust above and below it.

The cool dust forms a wind streaming outward from the black hole. This "wind" probably plays an important role in the complex relationship between the black hole and its environment. While the black hole gobbles down surrounding material, the intense radiation that this produces blows the material away.

 Currently, though, scientists are still unsure what that relationship might be.  Obviously the two processes work together to allow a black hole to grow and evolve. Yet exactly how they do so is unclear; that said, the findings do add another piece to the picture.

Now, the researchers are on the hunt. Currently, they're waiting for MATISSE, a second generation instrument for the VLTI, to be completed. It's currently under construction, and could reveal even more insights into this cool dust.

"I am now really looking forward to MATISSE, which will allow us to combine all four VLT Unit Telescopes at once and observe simultaneously in the near- and mid-infrared-giving us much more detailed data," said Sebastian Honig, one of the researchers, in a news release. 

The findings are published in The Astrophysical Journal.