Astronomers expected to find an active black hole in a distant galaxy, but instead discovered a powerful source of high-energy neutrinos fueled by extreme star formation. The galaxy JCMT0402−0424, nicknamed "Shadow Blaster," was identified as the origin of the IC 210922A neutrino event detected by the IceCube Observatory in 2021. This discovery represents the first direct link between a dusty star-forming galaxy and a specific neutrino event, raising new questions about which objects in the universe produce these enigmatic particles.
Descubren a Shadow Blaster, la galaxia lejana que dispara neutrinos fantasma tutiempo.net/noticias/descu…
An international team led by Yuji Urata of MITOS Science Co., LTD. in Taiwan—including researchers from National Central University, Chung Yuan University, Tohoku University, Fukui University of Technology, and the National Astronomical Observatory of Japan—conducted observations using ALMA in the Atacama Desert. Gravitational lensing by a foreground galaxy allowed ALMA to capture four highly magnified images of Shadow Blaster. The galaxy is located approximately 11 billion light-years away (at a redshift of z = 2.988), meaning its light has traveled since the era of "cosmic noon," a period about three billion years after the Big Bang when star formation peaked. Shadow Blaster’s compact core, measuring just 1,500 to 1,700 light-years across, proved to be an incredibly dense reservoir of gas and dust where stars are born at a rate of hundreds of solar masses per year—an astonishing pace hundreds of times faster than in our own Milky Way.
The data revealed no signs of an active galactic nucleus or a central black hole. Instead, the energy originates from cosmic rays colliding with dense gas within a stellar "cauldron," which serves as the birthplace of these neutrinos. Theoretical models have long predicted that such extreme environments act as natural particle accelerators, where high-energy particles repeatedly strike gas within tangled magnetic fields to produce neutrinos. While it was previously thought that high-energy neutrinos were primarily generated by supermassive black holes in active galaxies, it is now clear that hidden stellar explosions within dusty galaxies also make a significant and previously underestimated contribution.
Computer simulations indicate that similar compact, dusty galaxies from the cosmic noon era could account for 15 to 20 percent of the total high-energy neutrino flux in the universe. Although not the dominant source, this contribution is substantial and, crucially, had remained hidden from direct observation until this discovery. Historically, astronomers focused their search for neutrino sources on bright active nuclei and gamma-ray bursts, overlooking this vast population of dusty star-forming systems. This finding reshapes our understanding of the concealed mechanisms behind the production of cosmic particles.
These results were published on June 17, 2026, in the journal Nature Astronomy. Together, ALMA in Chile and IceCube in Antarctica have demonstrated that to understand the origin of cosmic neutrinos, we must look beyond black holes to the most turbulent stellar nurseries hidden behind clouds of dust—veritable particle factories of the early universe.
