Astronomers have identified the largest radio jet from the early Universe to date. Such expansive radio jets have long evaded detection in the distant cosmos. This discovery offers astronomers crucial new perspectives on when the first jets emerged and how they influenced galaxy development.
For many years, observations have revealed that most galaxies house massive black holes at their centers. The influx of gas and dust into these black holes generates significant amounts of energy due to friction, resulting in brilliant galactic cores known as quasars, which launch jets of energetic particles. Though we often see radio jets in our local Universe—appearing in some nearby galaxies—they have been notably absent in the distant, early Universe until now.
Employing various telescopes, astronomers have detected a remarkable distant radio jet that extends a staggering 200,000 light-years—double the size of the Milky Way. This marks the largest radio jet discovered so early in the Universe’s history.* The jet was initially spotted using the Low Frequency Array (LOFAR) Telescope, a collaborative network of radio telescopes situated throughout Europe.
To gain a holistic view of the radio jet and the quasar generating it, subsequent observations were made in near-infrared light with the Gemini Near-Infrared Spectrograph (GNIRS) and in optical wavelengths using the Hobby Eberly Telescope. These observations are vital for enhancing our understanding of when and how the first significant jets formed in the Universe.
GNIRS is part of the Gemini North telescope, which is one segment of the International Gemini Observatory. This project has been partially funded by the U.S. National Science Foundation (NSF) and is managed by NSF NOIRlab.
“We aimed to find quasars with strong radio jets in the early Universe to learn more about how and when these jets originated and their role in galaxy formation,” explains Anniek Gloudemans, a postdoctoral research fellow at NOIRLab and the lead author of the findings published in The Astrophysical Journal Letters.
Understanding the quasar’s characteristics, such as its mass and its rate of matter consumption, is essential to trace its formation history. To evaluate these attributes, the team sought a specific light wavelength emitted by quasars known as the MgII (magnesium) broad emission line. Typically, this signal is detected in the ultraviolet spectrum. However, due to the Universe’s expansion, which stretches the emitted light to longer wavelengths, the magnesium signal reaches Earth in the near-infrared range, making it observable with GNIRS.
The quasar, designated J1601+3102, originated when the Universe was less than 1.2 billion years old—only 9% of its current age. While quasars can possess masses that exceed our Sun by billions of times, this particular one is relatively modest at 450 million times the mass of the Sun. The jets exhibit asymmetrical brightness and differing distances from the quasar, hinting at the influence of an extreme environment.
“Interestingly, the quasar fueling this colossal radio jet does not have an exceptionally massive black hole in comparison to other quasars,” notes Gloudemans. “This suggests that generating such powerful jets in the early Universe may not require an extraordinarily large black hole or an intense accretion rate.”
The earlier scarcity of large radio jets in the early Universe has been linked to interference from the cosmic microwave background—the persistent radiation that remains from the Big Bang. This backdrop radiation ordinarily diminishes the visibility of radio emissions from such distant entities.
“It is because this object is so extreme that we’re able to observe it from Earth, despite its vast distance,” remarks Gloudemans. “This discovery illustrates the potential of merging multiple telescopes that operate across varied wavelengths.”
“Initially, we expected the southern jet to be an unrelated nearby source, expecting it to appear small. So, it was quite a surprise when the LOFAR imagery revealed large, intricate radio formations,” adds Frits Sweijen, a postdoctoral research associate at Durham University and a co-author of this research. “The nature of this distant object poses challenges for detection at higher radio frequencies, emphasizing LOFAR’s unique capabilities and its collaborative potential with other instruments.”
Researchers still have many questions regarding how radio-bright quasars like J1601+3102 are distinct from others. It is still unclear what conditions are necessary for the creation of such powerful radio jets, or when the earliest jets in the Universe emerged. Thanks to the teamwork of Gemini North, LOFAR, and the Hobby Eberly Telescope, we are now closer to unlocking the mysteries of the early Universe.
Note
* For reference, a significant radio jet in the nearby Universe is the 23 million-light-year-long jet called Porphyrion, observed 6.3 billion years after the Big Bang.
