I think every generation of astronomers has its own reason to be glad they came of age when they did. For those older than me, there was Apollo and the ability to be part of the first planetary missions. For the generation before, it was the advent of radio astronomy and spacecraft in general. 

Our field is one that advances at the pace of technology and we each can take joy in the new things that come along in our lifetimes. For me, I look at one amusing advancement and a whole series of serious ones. That amusing advancement? The transition from researchers using hand-drawn transparencies to using PowerPoint presentations. 

Early in my career, I was treated to countless drawings of various imaginary monsters sitting in the cores of galaxies that were labeled everything from ‘quasar’ to ‘Seyfert’ or just plain ‘active galaxy’. At the time, it was unknown why all these different systems looked different from one another and why those differences were bigger or smaller depending on the wavelength of light being looked at.

Somewhere along the line, coincident with PowerPoint becoming more common, a unified theory of active galactic nuclei (AGN) was put forward that explained all these objects are varying configurations of a galaxy with dust and gas swirling into a supermassive black hole and jets of material being ejected away with a magnetic field. Exactly what we see depends on how much material is being consumed and the angle we are seeing the system at. When we see a galaxy edge-on, versus looking straight down the jet, the systems can look completely different, but it is all just a trick of perspective.

And this theory has consistently worked to explain the myriad feeding black holes we’ve peered at, but we haven’t had those final proof images that demonstrate “yes, all these things are the same”. At least not until now. 

New images of the galaxy Messier 77, which is a good small telescope object, have allowed astronomers to resolve the material closest to the heart of this system and see how it is blocking our view of the galaxy’s supermassive black hole. This is the first time there has been clear observational evidence of material completely blocking the light from a black hole’s surroundings.

These results appear in the journal Nature in a paper led by Violeta Gámez Rosas and showcase the power of the Very Large Telescope’s four massive telescopes being used together. As Gámez Rosas explains: The real nature of the dust clouds and their role in both feeding the black hole and determining how it looks when viewed from Earth have been central questions in AGN studies over the last three decades. Whilst no single result will settle all the questions we have, we have taken a major step in understanding how AGNs work.

I wish more of those hand-drawn monsters had made it into the PowerPoint age and lived on in digital prosperity. That said, I’m really glad future astronomers can say, “Yes, we know all these things are driven by the same physics.”

More Information

ESO press release

“Thermal imaging of dust hiding the black hole in NGC 1068,” Violeta Gámez Rosas et al., 2022 February 16, Nature