- Hubble discovered a young quasar jet in a spiral galaxy.
- Quasar jets are typically found in elliptical galaxies.
- This discovery challenges the idea that quasars form only in merging galaxies.
Young quasar jet in spiral galaxy
The night sky has always played a crucial role in navigation, from early ocean crossings to modern GPS. Besides stars, the United States Navy uses quasars as beacons. Quasars are distant galaxies with supermassive black holes, surrounded by brilliant hot disks of swirling gas that can blast off jets of material.
Following up on the 2020 discovery of newborn jets in a number of quasars, Olivia Achenbach of the United States Naval Academy has used NASA’s Hubble Space Telescope to reveal surprising properties of one of them, quasar J0742+2704. Achenbach, who made the discovery a four-week internship, said:
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, after going through messy mergers and have come out with an elliptical shape.
Typical quasar-hosting galaxies
Nyland also commented:
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.
The unusual quasar takes its place amid an active debate in the astronomy community over what triggers quasar jets. It can be significant in the evolution of galaxies, as the jets can suppress star formation. Some astronomers suspect that quasar jets are triggered by major galaxy mergers. 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.
While J0742+2704 has maintained its 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.
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.
Another ring galaxy is nearby
Also another galaxy that appears nearby in the Hubble image (though its location still needs to be spectroscopically confirmed) has a ring structure. This rare shape can occur after a galaxy interaction in which a smaller galaxy punches through the center of a spiral galaxy. Nyland indicated:
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 this intriguing discovery is really a new starting point, and 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. It’s also a case for keeping our eyes on the skies. Achenbach concluded:
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