Sky Hotspots: The Senders of Ultra-Particles Identified ⚡ экспресс
The origin of ultra-high-energy cosmic rays (UHECRs) remains a central mystery of particle astrophysics. Recent measurements have revealed an anisotropy in arrival directions, a rigidity-dependent composition with a dominance of intermediate-mass nuclei, and significant hemispheric differences in energy spectra. It is shown that these features can be naturally explained by rare transient events in nearby galaxies — in particular, neutron star mergers. Within a basic model, such a scenario leads to a particle flux above 25 EeV being governed by the ten nearest galaxies within 8 Mpc. Seven of the ten brightest galaxies fall into registered regions of excess events, which has a probability of chance coincidence p≈0.001. Moreover, nearby transients account for the excess of Telescope Array data over the results of the Pierre Auger Observatory and modify the rigidity-ordered sequence of isotopes.
Every day, particles with colossal energy enter Earth's atmosphere—like unsigned letters. Their source long remained a mystery. New research shows: these 'visitors' point to nearby galaxies, where from time to time catastrophes occur—collisions of neutron stars, ultra-dense spheres the size of a city but with the mass of the Sun. Upon impact, they scatter particles like postal items, and some fly straight to us.
The same model explains why the northern and southern hemispheres see a slightly different 'assortment' of particles: simply, the nearest 'post offices'—the sources—are located on different sides of the sky. Previously, it was thought that the composition of rays depends only on energy, but now it's clear: the key to the puzzle lies in the arrangement of the sender galaxies.
🎯 One such particle, smaller than an atom, carries energy comparable to a baseball's impact—like a carrier pigeon delivering a truck.