Astronomers Discover Colossal Radio Jet From Early Universe

Astronomers have spotted a massive radio jet in the early universe, which they say is the largest known from that era.

The jet is at least 200,000 light-years long, making it twice the width of the Milky Way. It formed when the universe was less than 10% its current age of roughly 13.77 billion years. Though the jet is not the largest in the universe’s known history, its size and remarkable age raises questions about the source of these jets—some of the most exotic objects in the universe. The team’s research describing the jet is published today in The Astrophysical Journal Letters.

“There is this idea that maybe the most powerful jets are created from the most massive black holes or black holes that are heavily accreting material near the theoretical limit,” said Anniek Gloudemans, an astronomer at NOIRLab and lead author of the research, in an email to Gizmodo. “Therefore we were maybe expecting this newly discovered jet to host an extra-ordinary black hole, but this wasn’t the case.”

Radio jets are familiar objects in our nearby universe, but are much rarer—or at least less-known—in the early universe. The recently studied jet spews out from a quasar, or an energetic galactic core, dubbed J1601+3102. Astronomers first identified the jet in Low Frequency Array (LOFAR) Telescope data, and details of the jet and its source quasar were collected via observations with the Gemini Near-Infrared Spectrograph (GNIRS) and the Hobby Eberly Telescope.

The jet is seen below spewing from its quasar, a reddish splotch, when the universe was less than 1.2 billion years old. The quasar in question is relatively small—just 450 million times the mass of our Sun. Thus, the extremity of the jet is a surprise compared to its relatively modest host.

The quasar jet. Image: LOFAR/DECaLS/DESI Legacy Imaging Surveys/LBNL/DOE/CTIO/NOIRLab/NSF/AURA
Image processing: M. Zamani (NSF NOIRLab)

According to a NOIRLab release, the scarcity of large radio jets so far back in time may be due to radiation from the cosmic microwave background, whose noise drowns out radio light. The only reason the team was able to see this particular jet is that it is huge for its age.

The largest known jets, which together form a megastructure called Porphyrion, were discovered last year and are 23 million light-years long. That’s more than ten times the size of J1601+3102’s jet. If Porphyrion’s jets were only as wide as our planet, the black hole that powers them would be the size of an amoeba. However, Gloudemans’ team can only see J1601+3102’s jet as it appears at this moment in the early universe.

“We observed this jet as it was 12.4 billion years ago, so over time it will have grown larger. Porphyrion is an extremely large giant at a distance of about 7.5 billion light years,” Gloudemans said. “Our newly discovered jet doesn’t come close to the 23 million light year size of Porphyrion, however, it does provide evidence of large radio jets already in place earlier in the history of the Universe.”

An artist’s impression of the gigantic black hole jet system extending through the cosmos. Illustration: E. Wernquist / D. Nelson (IllustrisTNG Collaboration) / M. Oei

The researchers who studied Porphyrion posited that such large jets likely affect the growth of their host galaxies and others nearby.

Plenty of questions remain, including how jets are formed by their environments and in turn shape them. The jury’s also out on what massive objects produce what kinds of jets, and just how big the jets can grow. As astronomers collect more observations—new instruments like the Square Kilometer Array will help them in their search—the incredible diversity of these extreme objects and their origins may become clear.