A high-energy neutrino detected on Earth has been traced back to a distant galaxy nicknamed Shadow Blaster, located about 11 billion light-years away. The particle, known as IC 210922A, was picked up by the IceCube Neutrino Observatory in Antarctica. The research reported that this may be one of the strongest hints so far linking a single galaxy to a high-energy neutrino event.
Neutrinos are often described as “ghost particles” because they barely interact with matter. They pass through planets, stars, and even human bodies almost unnoticed. That makes them extremely hard to trace, even though they are constantly flowing through the universe in huge numbers.
The difficulty is that detecting a neutrino is only half the story. The real challenge is figuring out where it came from. In this case, scientists followed the signal back toward the constellation Eridanus and began searching across multiple wavelengths for any matching cosmic event.
A Quiet Sky After A Powerful Signal
When IceCube recorded IC 210922A in 2021, astronomers immediately searched for a clear astrophysical source. The study, published in the journal Nature Astronomy stated that they looked for gamma-ray bursts, exploding stars, and tidal disruption events caused by black holes tearing stars apart.
Researchers found no accompanying gamma-ray, X-ray, or optical emission, leaving the neutrino event unexplained. Even with several observatories scanning the area, the sky remained surprisingly quiet.
They eventually expanded their approach, turning to longer wavelengths where dusty, hidden galaxies are easier to detect.
Shadow Blaster Revealed Through Cosmic Lensing
The key breakthrough came with data from the James Clerk Maxwell Telescope (JCMT) and the Submillimeter Array (SMA), which identified a bright infrared source labeled JCMT0402−0424. It was later given the nickname Shadow Blaster.
Further observations with ALMA in Chile and the Gemini North telescope helped clarify the picture. These showed that Shadow Blaster is a dusty, gas-rich galaxy undergoing intense star formation.
It is also strongly affected by gravitational lensing, where a massive object between Earth and the galaxy bends and magnifies its light. Thanks to that natural “cosmic zoom,” astronomers were able to study a system that would otherwise be extremely faint and difficult to observe at such a distance.
One important detail is that Shadow Blaster does not show signs of a strongly active supermassive black hole producing powerful jets. Instead, the activity seems dominated by star formation inside dense regions of gas and dust.
Starburst Galaxies Under The Spotlight
Shadow Blaster belongs to a category known as starburst galaxies, where stars form at unusually high rates. These environments are chaotic, packed with dense gas clouds and energetic processes that can reshape how particles move through space.
Researchers think these conditions could be enough to accelerate particles to extremely high energies, including neutrinos.
“Shadow Blaster possesses the kind of dense, gas-rich environment that theoretical models have long suggested could efficiently produce high-energy neutrinos,”Yuji Urata of MITOS Science Co. Ltd. in Taiwan explained in a statement.
He added that, if confirmed, Shadow Blaster would represent the first individual dusty star-forming galaxy directly connected to a high-energy neutrino event.
There is also a broader implication. Starburst galaxies were far more common around 10 billion years ago, when the universe was much more active in forming stars. That makes them interesting candidates for contributing to the overall neutrino background detected today.
Findings suggest that galaxies like these could account for up toroughly 20% of the diffuse high-energy neutrino background measured by IceCube. If that estimate holds, it would mean that not all high-energy neutrinos come from black hole systems, but also from dense, rapidly evolving star-forming regions spread across cosmic history.
