Astronomers spot the ‘Eye of Sauron’ in deep space

A stunning new image of a cosmic jet has helped astronomers unlock the mystery behind the unusually bright emission of high-energy gamma rays and neutrinos from a peculiar celestial object. The source is a blazar—a type of active galaxy powered by a supermassive black hole devouring matter at the heart of a galaxy. They have captured what looks like the mythical “Eye of Sauron” in the distant universe and may have just solved a decade-long cosmic puzzle.

The researchers made a discovery that will help in understanding how a seemingly slow-moving blazar, known as PKS 1424+240, could be one of the brightest sources of high-energy gamma rays and cosmic neutrinos ever observed. The work is published in the journal Astronomy & Astrophysics.

Located billions of light-years away, the blazar PKS 1424+240 had long baffled astronomers. It stood out as the brightest known neutrino-emitting blazar in the sky—as identified by the IceCube Neutrino Observatory—and was also glowing in very high-energy gamma rays observed by ground-based Cherenkov telescopes. Yet, oddly, its radio jet appeared to move sluggishly, contradicting expectations that only the fastest jets could be behind such exceptional brightness.

Now, thanks to 15 years of ultra-precise radio observations from the Very Long Baseline Array (VLBA), researchers have stitched together a deep image of this jet at unparalleled resolution.

“When we reconstructed the image, it looked absolutely stunning,” says Yuri Kovalev, lead author of the study and Principal Investigator of the MuSES project at the Max Planck Institute for Radio Astronomy (MPIfR). “We have never seen anything quite like it—a near-perfect toroidal magnetic field with a jet, pointing straight at us.”

Because the jet is aligned almost exactly in the direction of Earth, its high-energy emission is dramatically amplified by the effects of special relativity. “This alignment causes a boost in brightness by a factor of 30 or more,” explains Jack Livingston, a co-author at MPIfR. “At the same time, the jet appears to move slowly due to projection effects—a classic optical illusion.”

This head-on geometry allowed scientists to peer directly into the heart of the blazar’s jet—an extremely rare opportunity. Polarized radio signals helped the team map out the structure of the jet’s magnetic field, revealing its likely helical or toroidal shape. This structure plays a key role in launching and collimating the plasma flow, and may be essential for accelerating particles to extreme energies.

“Solving this puzzle confirms that active galactic nuclei with supermassive black holes are not only powerful accelerators of electrons, but also of protons—the origin of the observed high-energy neutrinos,” concludes Kovalev.

The discovery is a triumph for the MOJAVE program, a decades-long effort to monitor relativistic jets in active galaxies using the Very Long Baseline Array (VLBA). Scientists employ the technique of Very Long Baseline Interferometry (VLBI), which connects radio telescopes across the globe to form a virtual telescope the size of Earth. This provides the highest resolution available in astronomy, allowing them to study the fine details of distant cosmic jets.

“When we started MOJAVE, the idea of one day directly connecting distant black hole jets to cosmic neutrinos felt like science fiction. Today, our observations are making it real,” says Anton Zensus, Director at MPIfR and co-founder of the program.

This result strengthens the link between relativistic jets, high-energy neutrinos, and the role of magnetic fields in shaping cosmic accelerators—marking a milestone in multimessenger astronomy.