Astronomers believe they have traced the origin of a ghostly cosmic particle to a distant star-forming galaxy nicknamed the ‘Shadow Blaster’, located 11 billion light-years away.
Cosmic Particles and Star-Forming Galaxies
Neutrinos, also known as ghost particles, are abundant across the universe and possess no electric charge, have little mass, and don’t seem to interact with other types of matter. They can be created by supernovae, stellar nuclear reactions, and the breakdown of heavy particles.
However, tracing the origin of neutrinos has proven difficult due to their ability to travel across the universe almost undisturbed. Even when detectors such as Antarctica’s IceCube Neutrino Observatory alert their presence, the position on the sky often has an uncertainty region that is much larger than the size of a galaxy.
The Discovery
Lead author Dr. Yuji Urata and his team encountered a stroke of luck when a cosmic coincidence brightened the Shadow Blaster galaxy shortly after the detection of a high-energy neutrino on Earth. This suggested a flare of activity that led the researchers to the galaxy and could point to a new way to search for the origins of ghost particles.
The event that created the neutrino, named IC 210922A, appeared to occur in the direction of the Eridanus constellation, and the observatory released an alert to the astronomy community. Scientists carried out quick follow-up observations across different wavelengths of light to seek out the particle’s origin point.
Although they were unsuccessful in detecting any exploding stars, gamma-ray bursts, X-rays, or visible light components that might be associated with the neutrino, the team discovered a galaxy rich with star formation called JCMT0402−0424, which had trillions of times the luminosity of our sun in infrared light.
The galaxy, nicknamed Shadow Blaster, is filled with dust, making it nearly invisible in optical light, X-rays, or gamma rays. However, the team was able to study a hidden, compact star-forming region that would otherwise have been much harder to detect due to a gravitational lensing effect.
Dense stellar nurseries in galaxies, such as the one in Shadow Blaster, can provide the gas, radiation, and magnetic environments that act like particle accelerators to produce neutrinos. Star-forming galaxies such as Shadow Blaster could be a key source of high-energy neutrinos, with the team’s analysis suggesting that this population could contribute up to roughly 20% of the observed diffuse neutrino background measured by IceCube.
Original reporting: KEYT (Ventura/Santa Barbara) — read the source article.
