Colossal Radio Jet from Ancient Quasar Surpasses Milky Way in Size

Scientists have identified the most immense and oldest radio jet ever observed, originating from a quasar dating back to when the cosmos was merely 1.2 billion years old. This extraordinary structure, named J1601+3102, was imaged by the LOFAR telescope network and extends an astonishing 200,000 light-years, making it almost three times wider than our Milky Way galaxy. Published in The Astrophysical Journal Letters, this finding sheds light on the intense phenomena influencing early galactic evolution and reveals surprising aspects of how relatively modest black holes operated in the young universe.

Huge Jet Powered by a Relatively Small Black Hole

The quasar J1601+3102 is notable not only for the immense scale of its jet but also for its origin. Existing when the universe was just nine percent of its current age, this quasar is fueled by a black hole holding about 450 million solar masses. While large, this mass is not exceptional among quasars. “The fact that this huge radio jet comes from a quasar without an extremely massive black hole suggests powerful jets can arise even without exceptional black hole mass or accretion rates in the early cosmos,” states Anniek Gloudemans, postdoctoral fellow at NOIRLab and the study’s lead author.

These radio jets consist of charged particles propelled near the speed of light, creating glowing lobes observable in radio frequencies. In this instance, each lobe extends approximately 66,000 light-years from the central quasar. Their detectability over a span exceeding 12 billion years highlights the immense energy involved. Gloudemans adds, “Its extreme nature enables us to detect it despite its vast distance.”

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How LOFAR Uncovered Hidden Details

The discovery was made possible by the Low Frequency Array (LOFAR), a collaborative European telescope array. Spanning more than 50 stations from Ireland to Poland, LOFAR functions as one giant antenna that captures very long radio wavelengths. These low frequencies are ideal for unveiling the faint radio lobes of faraway galaxies, often missed by other instruments. “Initially, we thought the southern jet was a nearby, unrelated source and expected it to be small,” recalls Frits Sweijen, postdoctoral researcher at Durham University and co-author. “The detailed and large radio structures revealed by LOFAR were quite a surprise.”

Thanks to LOFAR’s exceptional sensitivity, researchers can detect diffuse electron clouds rather than only the brightest jet sections. “This distant object is challenging to observe at higher radio frequencies, highlighting LOFAR’s unique capabilities and its complementarity with other instruments,” adds Sweijen. Without LOFAR, the full scale of J1601+3102 might have remained concealed beneath the overwhelming glow of the cosmic microwave background radiation from the Big Bang.

Combining Multiple Observations for a Complete Image

While LOFAR provided the initial insight, understanding J1601+3102 required additional data from other wavelengths. Infrared data from the Gemini North Telescope in Hawai‘i and optical spectroscopy from the Hobby-Eberly Telescope in Texas helped confirm the quasar’s distance and analyze the redshifted magnesium emission lines, offering clues about the galaxy’s motion and black hole accretion processes.

“This discovery underscores the power of multi-wavelength astronomy,” Gloudemans commented. Different instruments revealed various facets—from jet morphology to host galaxy characteristics and the interaction between the jet and its cosmic environment. Notably, the southern lobe appears truncated, likely due to collisions with gas clouds or adjacent halos, while the northern lobe freely extends into the intergalactic medium. These asymmetries provide valuable insights into early galaxy formation and their environmental effects.