One of the brightest objects in the cosmos just had its close-up.
Using the Hubble Space Telescope, astronomers homed in on a quasar called 3C 273, some 2.5 billion light-years from Earth. It’s one of the closest quasars to Earth, and extremely bright, making it a prime target for understanding the forces that illuminate these fascinating galaxies.
The new observations reveal some of the galaxy’s distinct structures that we’ve never been able to tease out before, which not only tells us about the object itself – it validates a new method for understanding how quasars work.
“Thanks to Hubble’s observing power, we’re opening a new gateway into understanding quasars,” says astronomer Bin Ren of the Côte d’Azur Observatory and Université Côte d’Azur in France. “My colleagues are excited because they’ve never seen this much detail before.”
Quasars are awe-inspiring – among the brightest objects in the Universe, behind gamma-ray bursts and supernovae. Unlike other bright objects, though, quasars stick around. They are thought to be powered by supermassive black holes that lurk at the heart of each galaxy.
Black holes emit no light we can detect on their own. But the gas and dust around a feeding black hole does. That material swirls around in a disk, raining down onto the black hole from its inner rim. The gravity and friction within the disk are so high that they heat it to astonishing temperatures, causing the material to blaze with light across the spectrum, a last scream of brilliance before it vanishes into the darkness forever.
That is the light we see when we look at a quasar. But they’re all really far away; and even the ones that are closer are so bright that features are difficult to resolve. 3C 273 is not the closest quasar to Earth, but it is among the brightest from our perspective, shining with the light of trillions of Suns, all packed into a tiny galactic center. It’s so bright that you can see it with a backyard telescope, even across 2.5 billion light-years.
To see the structures that might be hiding in this light, the new Hubble observations used the Space Telescope Imaging System (STIS) to create a makeshift coronagraph that obscures the brightest source of light. It’s a bit like holding a hand in front of your eyes when someone is shining a flashlight right at you – it allows you to see the other things the light is illuminating without being blinded by glare.
The new observations, eight times closer than any obtained previously, revealed never-before-seen details in the structures around the center of the quasar, within a radius of 16,000 light-years.
The researchers identified small blobs that may be satellite galaxies or chunks of material in the process of being subsumed by the quasar. They also found a new core jet, and a mysterious L-shaped filament that is yet to be identified.
In addition, they made new measurements of the astrophysical jet launched by the black hole’s external magnetic field, and extending 300,000 light-years into intergalactic space, constraining its motion over a 22-year timeframe. This analysis revealed that the jet appears to be moving faster the farther it gets from the black hole.
What this all means and the mechanisms behind it are yet to be unraveled. Obtaining the data is an important step that will enable astronomers to conduct deeper analyses to better understand both 3C 273 in specific, and, hopefully, quasar behavior in general.
“With the fine spatial structures and jet motion, Hubble bridged a gap between the small-scale radio interferometry and large-scale optical imaging observations, and thus we can take an observational step towards a more complete understanding of quasar host morphology,” Ren says.
“Our previous view was very limited, but Hubble is allowing us to understand the complicated quasar morphology and galactic interactions in detail. In the future, looking further at 3C 273 in infrared light with the James Webb Space Telescope might give us more clues.”
The research has been published in Astronomy & Astrophysics.
