Star Mergers' Magnetic Outflows Spawn Universe's Highest-Energy Particles
by Clarence Oxford
Los Angeles CA (SPX) Mar 01, 2025

Ultrahigh Energy Cosmic Rays (UHECRs) are the most energetic particles known in the universe, with energies exceeding those attainable by human-made accelerators by more than a million times. Despite their discovery over six decades ago, the origin of these extreme particles has remained an open question in astrophysics.

A groundbreaking theory by Glennys Farrar, a physicist at New York University, now provides a compelling explanation for their formation.

"After six decades of effort, the origin of the mysterious highest-energy particles in the universe may finally have been identified," said Farrar, a Collegiate Professor of Physics and Julius Silver, Rosalind S. Silver, and Enid Silver Winslow Professor at NYU. "This insight gives a new tool for understanding the most cataclysmic events of the universe: two neutron stars merging to form a black hole, which is the process responsible for the creation of many precious or exotic elements, including gold, platinum, uranium, iodine, and xenon."

Farrar's study, published in Physical Review Letters, suggests that UHECRs are propelled by the turbulent magnetic outflows of Binary Neutron Star mergers. These particles are ejected from the merger remnant before the final black hole fully forms. This process also generates intense gravitational waves, some of which have already been detected by the LIGO-Virgo collaboration.

This novel framework resolves two long-standing mysteries about UHECRs: the consistent correlation between a UHECR's energy and its electric charge, and the exceptionally high energy levels observed in a select few cosmic ray events.

Farrar's findings also present testable predictions for future research:

- The highest-energy UHECRs originate as rare "r-process" elements, such as xenon and tellurium, warranting a targeted search for these elements in UHECR data.

- Extremely high-energy neutrinos, produced in UHECR collisions, should appear alongside the gravitational waves from their parent neutron star mergers.

These insights not only provide a framework for understanding UHECRs but also establish a pathway for future observational validation.

Research Report:Binary Neutron Star Mergers as the Source of the Highest Energy Cosmic Rays

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