Hubble Reveals Surprising Spiral Shape of Galaxy Hosting Young Jet

NASA · January 13

4 Min Read

Hubble Reveals Surprising Spiral Shape of Galaxy Hosting Young Jet

Field of yellow galaxies of various sizes and distances on a black background. Two larger galaxies are prominent. Centered is a galaxy with a bright core and faint spiral arms coming off its top and bottom. To the lower right of the spiral is a ring galaxy with an apparent gap between its bright core and the ring oval of dust and gas surrounding it.

Quasar J0742+2704

Credits:
NASA, ESA, Kristina Nyland (U.S. Naval Research Laboratory); Image Processing: Joseph DePasquale (STScI)

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 brilliantly hot disks of swirling gas that can blast off jets of material. Following up on the groundbreaking 2020 discovery of newborn jets in a number of quasars, aspiring naval officer 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.

“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,” said Achenbach, who made the discovery during the course of a four-week internship.

Quasar J0742+2704 (center) became the subject of astronomers’ interest after it was discovered to have a newborn jet blasting from the disk around its supermassive black hole in 2020, using the Karl G. Jansky Very Large Array (VLA) radio observatory. This led to follow-up with other observatories in an effort to determine the properties of the galaxy and what may have triggered the jet. While the jet itself cannot be seen in this Hubble Space Telescope infrared-light image, the spiral shape of J0742+2704 is clear, with faint but detectable arms branching above and below the galaxy center. This was a big surprise to the research team, as quasars hosting jets are typically elliptical-shaped, and its suspected that messy mergers with other galaxies are what funnel gas toward the black hole and fuel jets. These mergers would also disrupt any spiral formation a galaxy may have had before mixing its contents with another galaxy. Though its intact spiral shape means it has not experienced a major merger, Hubble does show evidence that its lower arm has been disrupted, possibly by the tidal forces of interaction with another galaxy. This could mean that jets can be triggered by a far less involved, dramatic interaction of galaxies than a full merger. The large galaxy to the lower right of the quasar appears to be a ring galaxy, another sign of interaction. Some ring galaxies form after a small galaxy passes through the center of a larger galaxy, reconfiguring its gas and dust. The brightest parts of this image — foreground stars and the bright center of the quasar — show the characteristic “starry” spikes produced by Hubble (and other telescopes’) interior structure. They are not actual aspects of the cosmic objects.

NASA, ESA, Kristina Nyland (U.S. Naval Research Laboratory); Image Processing: Joseph DePasquale (STScI)

“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,” said astronomer Kristina Nyland of the Naval Research Laboratory, Achenbach’s adviser on the research.

“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,” Nyland said.

The unusual quasar takes its place amid an active debate in the astronomy community over what triggers quasar jets, which 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, as 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.

Field of yellow galaxies of various sizes and distances on a black background, with text and labels. Two larger galaxies are prominent. Centered is a galaxy with a bright core and faint spiral arms coming off its top and bottom. Its bright core is circled with a dotted line and labeled Quasar. To the upper right of the spiral galaxy, an arc of faint gas is outlined with a dotted line and labeled Tidal Tail. To the lower right of the spiral is the second prominent galaxy, with an apparent gap between its bright core and an oval of dust and gas surrounding it, labeled Ring Galaxy. At the lower right corner of the image a compass points to North at 5 o'clock and East at 2 o'clock. Text at the upper left corner of the image reads J0742+2704, HST, WFC3/IR. The Hubble filter is indicated with text reading F140W in the same yellow color used on for the stars and galaxies.

Hubble captured intriguing hints of interaction, if not full merging, between galaxies including quasar J0742+2704. There is evidence of a distorted tidal tail, or a streamer of gas, that has been pulled out by the gravity of a nearby galaxy. The presence of a ring galaxy also suggests interaction: The distinctive shape of ring galaxies are thought to form when one galaxy passes through another, redistributing its contents into a central core circled by stars and gas. Astronomers will be doing further analysis of Hubble’s detailed spectroscopic data, plus follow-up with other telescopes that can see different types of light, to confirm the distances of the galaxies and how they may be affecting one another.

NASA, ESA, Kristina Nyland (U.S. Naval Research Laboratory); Image Processing: Joseph DePasquale (STScI)

“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,” said Nyland.

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. “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,” said Nyland.

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, said Achenbach.

“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,” said Achenbach. “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.”

The Hubble Space Telescope has been operating for over three decades and continues to make ground-breaking discoveries that shape our fundamental understanding of the universe. Hubble is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope and mission operations. Lockheed Martin Space, based in Denver, also supports mission operations at Goddard. The Space Telescope Science Institute in Baltimore, which is operated by the Association of Universities for Research in Astronomy, conducts Hubble science operations for NASA.