Ghost particle traced to star-forming galaxy 11B light-years away

Astronomers identified a galaxy nicknamed “Shadow Blaster,” 11 billion light-years away, as a candidate source for a neutrino detected by IceCube in Antarctica.nature
The finding challenges assumptions that high-energy neutrinos originate near active black holes, suggesting violent star formation alone can produce them.nao
Compact starburst galaxies like Shadow Blaster may account for roughly 20% of the high-energy neutrino background bathing Earth, according to the study.nature

Neutrino Traced to Distant Star-Forming Galaxy “Shadow Blaster”

Astronomers have linked a high-energy neutrino detected by the IceCube Observatory in Antarctica to a distant, dust-choked galaxy 11 billion light-years away — a finding that challenges long-held assumptions about where the universe’s most elusive particles originate.

A Ghost Particle Finds a Home

In a study published June 17 in Nature Astronomy, an international team led by Yuji Urata of MITOS Science Co. in Taiwan identified an extremely luminous galaxy cataloged as JCMT0402−0424, nicknamed “Shadow Blaster,” as a candidate source for one of IceCube’s high-energy neutrino detections. The galaxy, located at cosmic noon — the epoch roughly 11 billion years ago when the universe’s star formation peaked — shines with trillions of times the luminosity of the sun in the infrared.phys

Using the Gemini North telescope on Maunakea in Hawai’i, followed by observations with the Atacama Large Millimeter/submillimeter Array (ALMA), researchers determined that the galaxy’s immense energy output is driven entirely by intense star formation. Crucially, the team found no evidence of an active galactic nucleus — a feeding supermassive black hole — powering the system.nao

Star Formation as a Cosmic Accelerator

The finding upends the prevailing view that high-energy neutrinos must come from environments around active black holes. Previous IceCube results had pointed to active galaxies like NGC 1068 as neutrino sources. Shadow Blaster suggests a different mechanism: the violent processes of star birth alone — supernovae, stellar winds, and shockwaves coursing through dense gas — can accelerate cosmic rays to energies high enough to produce neutrinos.utah

“If confirmed, Shadow Blaster would be the first-ever individual dusty star-forming galaxy directly linked to a high-energy neutrino event,” researchers noted.courthousenews

Implications for the Neutrino Background

The team estimates that compact, gas-rich starburst galaxies like Shadow Blaster could account for roughly 20 percent of the diffuse high-energy neutrino background that IceCube has measured washing over Earth from all directions. This connects neutrino production to the peak epoch of cosmic star formation, opening what the authors describe as a new avenue to probe galaxy evolution using neutrino astronomy.nature

The result was announced jointly by NOIRLab, which operates Gemini North, and the National Astronomical Observatory of Japan, which co-operates ALMA.nao