University of Copenhagen researchers map Milky Way stellar neutrinos

University of Copenhagen researchers map Milky Way stellar neutrinos

Researchers at the University of Copenhagen have developed a comprehensive model detailing the production and distribution of neutrinos emitted by stars throughout the Milky Way. This mapping provides a concrete estimate of the number of particles reaching Earth, their origins within the galaxy, and the distribution of their energy.

Neutrinos, often called ghost particles, are electrically neutral, lightweight elementary particles that rarely interact with matter. Because they can travel in straight lines through dust clouds and magnetic fields, and escape the dense interiors of stars, they carry information directly from stellar cores that light and other radiation cannot provide.

The team, based at the Niels Bohr Institute, created this neutrino weather map by combining stellar evolution calculations with precise star-position data from the European Space Agency's Gaia telescope. The researchers focused on the steady neutrino output of stars rather than violent explosions, accounting for neutrinos created via thermal processes and nuclear reactions.

According to the model, the strongest neutrino flow toward Earth originates from the galactic center, where stars are most densely packed. The study found that the highest signals come from stars that are as massive or more massive than the Sun, specifically those that are younger.

"For the first time, we have a concrete estimate of how many of these particles reach Earth, where in the galaxy they come from, and how their energy is distributed,"

Pablo Martínez-Miravé, postdoc at the Niels Bohr Institute, via yahoo.com

This roadmap is intended to assist operators of underground neutrino observatories. Because these detectors cannot be aimed like traditional telescopes and must wait for rare interactions, knowing the expected energy range and the brightest directions allows scientists to focus their analyses and improve the odds of detecting a faint galactic signal against background noise.

Beyond mapping, the research suggests a potential for discovering new physics. Because neutrinos are barely affected by their environment, physicists have clear expectations of their behavior. Senior author Irene Tamborra, a professor at the Niels Bohr Institute, stated that even tiny deviations in their behavior on the journey to Earth would be a strong clue to new, unknown physics.

The findings, available in the journal Physical Review D, may eventually allow researchers to probe stellar interiors across the galaxy. This could refine models of how stars age and burn fuel, as well as clarify the overall structure of the Milky Way.

Parallel discoveries in high-energy particles

While the Copenhagen team mapped the steady flow of stellar neutrinos, other international efforts have focused on more violent particle accelerators. On July 16, 2026, a Hiroshima University-led team published findings in The Astrophysical Journal identifying a proton PeVatron — an accelerator of the highest-energy cosmic-ray protons — known as LHAASO J1912+1014u.

Located in the constellation Aquila near the star Altair, LHAASO J1912+1014u was previously thought to be a supernova remnant. However, the research team used a bundled approach of multiwavelength modeling, combining GeV gamma-ray data from NASA's Fermi Large Area Telescope (Fermi-LAT), radio data from the FOREST Unbiased Galactic plane Imaging survey (FUGIN), and X-ray data from the Chandra X-ray Observatory.

This analysis confirmed the source as a proton PeVatron, where particles reach or exceed one quadrillion (1015) electron volts, or a peta electron volt (PeV). Associate professor Tsunefumi Mizuno noted that the GeV gamma-ray map aligned with the interstellar gas distribution traced by FUGIN, while Chandra data showed very weak diffuse X-ray emission, ruling out other scenarios.

Separately, the Large High Altitude Air Shower Observatory (LHAASO) released results on November 16, 2025, linking the knee of the cosmic ray energy spectrum, a drop in counts above 3 PeV, to micro-quasars. These are black holes in binary systems that feed on companion stars and create relativistic jets.