Astronomers have taken a close-up image of a radio jet emitted by a supermassive black hole for the first time. The Event Horizon Telescope (EHT) has zoomed in on this jet with 16 times the resolution and at 10 times higher frequencies than previous observations to learn more about this strange phenomenon.
By name and nature, black holes are pretty much invisible, but they can reveal themselves through the extreme environment they create. As they suck in dust and gas, this material heats up and glows in a disc, creating a bright background on which the silhouette of the black hole can be seen.
In April 2019, the EHT Collaboration unveiled the first ever direct images of a black hole using this method, showing us the supermassive monster at the heart of the galaxy Messier 87. Follow-up analysis earlier this year showed the polarization of the light from the disc.
Now, the Collaboration has turned its attention to a different black hole, located at the center of the radio-bright galaxy Centaurus A. With a mass of 55 million Suns, it’s a fraction of M87’s 6.5-billion-solar-mass black hole, but the main difference is that Centaurus A is an active galaxy, firing off gigantic jets of material from its central black hole. And this is what the team has now imaged closer than ever.
"This allows us for the first time to see and study an extragalactic radio jet on scales smaller than the distance light travels in one day,” says Michael Janssen, corresponding author of the study. “We see up close and personally how a monstrously gigantic jet launched by a supermassive black hole is being born.”
The clarity of the image reveals new clues about the nature of these jets. The radiation seems to be brighter around the edges than at the center, which may help rule out some models of how they’re produced. The team was also able to narrow down where exactly the black hole was in the region, by following the path of the jet back to its point of origin. That could guide future observations using shorter wavelengths and higher resolutions to image the black hole itself.
The research was published in the journal Nature Astronomy.
Source: Event Horizon Telescope
