Hubblesite originally released this article on January 13, 2025. Edits by EarthSky.
- Hubble discovered a young quasar jet in a spiral galaxy.
- Quasar jets are typically found in elliptical galaxies, which are often born in galaxy mergers.
- This discovery challenges the idea that quasars form only in merging galaxies.
Spiral galaxy hosting a quasar jet
From early ocean crossings to modern GPS, the night sky has played a crucial role in navigation. Today, the United States Navy uses not just stars, but also distant quasars – blazingly bright objects, thought to be located at vast distances from Earth – as beacons. Quasars are thought to reside in distant galaxies with supermassive black holes at their hearts. They’re thought to be surrounded by brilliant hot disks of swirling gas that can blast off jets of material. These quasar jets are most often found in large elliptical galaxies, thought to have formed in galaxy mergers. But a recent discovery mysteriously shows a quasar jet in a spiral galaxy.
Olivia Achenbach of the United States Naval Academy made the discovery during the course of a four-week internship. She was using NASA’s Hubble Space Telescope to help reveal surprising properties in a quasar called J0742+2704. Achenbach commented:
The biggest surprise was seeing the distinct spiral shape in the Hubble Space Telescope images. At first, I was worried I had made an error.
Kristina Nyland of the Naval Research Laboratory, Achenbach’s adviser on the research, added:
We typically see quasars as older galaxies that have grown very massive, along with their central black holes … [we see usually see them] after they’ve gone through messy mergers and have come out with an elliptical shape.
It’s extremely rare and exciting to find a quasar-hosting galaxy with spiral arms and a black hole that is more than 400 million times the mass of the sun — which is pretty big — plus young jets that weren’t detectable 20 years ago.
Typical quasar-hosting galaxies
The unusual quasar takes its place amid an active debate in the astronomy community over what triggers quasar jets. Some astronomers suspect that quasar jets are triggered by major galaxy mergers. They think that, when the material from two or more galaxies mashes together, and heated gas is funneled toward merged black holes. Spiral galaxy quasars like J0742+2704, however, suggest that there may be other pathways for jet formation.
Although J0742+2704 has a spiral shape, the Hubble image does show intriguing signs of its potential interaction with other galaxies. One of its arms shows distortion, possibly a tidal tail, that is, a long stream of material pulled out via gravity (much as Earth’s moon pulls on Earth’s oceans to create tides). According to Nyland:
Clearly there is something interesting going on. While the quasar has not experienced a major disruptive merger, it may be interacting with another galaxy, which is gravitationally tugging at its spiral arm.
A ring galaxy might be nearby
Also another galaxy that appears nearby in the Hubble image has a ring structure. The ring galaxy’s location still needs to be spectroscopically confirmed; it’s possible it lies some distance away, in the foreground. But, if it is near the quasar in space, the rare ring shape might also be a sign of galaxy interaction. Some ring galaxies are thought to form when a smaller galaxy punches through the center of a spiral galaxy. Nyland said:
The ring galaxy near the quasar host galaxy could be an intriguing clue as to what is happening in this system. We may be witnessing the aftermath of the interaction that triggered this young quasar jet.
Both Achenbach and Nyland emphasize that the discovery of the quasar jet is a spiral galaxy is a starting point. They said there will be additional multi-wavelength analysis of J0742+2704 with data from NASA’s Chandra X-ray Observatory and the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile. The discovery is also a case for keeping our eyes on the skies, Achenbach said:
If we looked at this galaxy 20 years, or maybe even a decade ago, we would have seen a fairly average quasar and never known it would eventually be home to newborn jets. It goes to show that if you keep searching, you can find something remarkable that you never expected, and it can send you in a whole new direction of discovery.
Bottom line: A recent Hubble image reveals a spiral galaxy hosting quasar. Typically, quasars are older galaxies that have grown very massive and are not spiral shaped.
Via NASA
Read more: 1st pair of merging quasars seen at Cosmic Dawn