Astroparticle Physics and High-Energy Cosmic Phenomena

Astroparticle physics explores the fundamental particles and forces at play in the Universe by studying cosmic messengers—chiefly cosmic rays, neutrinos and high-energy photons—that originate from astrophysical accelerators. These phenomena span a vast energy range, from gigaelectronvolts to exaelectronvolts, and probe environments such as supernova remnants, active galactic nuclei jets, gamma-ray bursts and merging compact objects. Particles accelerated in shock fronts or reconnection layers interact with ambient matter and radiation fields, producing secondary neutrinos and gamma rays via photohadronic and hadronic processes. Observations by ground-based air-shower arrays, deep-sea and polar ice neutrino telescopes, as well as satellite-borne detectors, have established a multi-messenger framework that integrates electromagnetic, neutrino and cosmic-ray data. This synergy offers unique insights into the mechanisms of particle acceleration, the composition and propagation of cosmic rays through interstellar and intergalactic media, and fundamental physics such as neutrino oscillations and potential signatures of dark matter. Advances in detector sensitivity, computational modelling and real-time alert systems are rapidly transforming our understanding of the high-energy Universe, revealing both steady and transient sources and mapping their contribution to the diffuse backgrounds that permeate space.

Research from Nature Portfolio

Recent studies have identified a promising abyssal plain site in the western Pacific Ocean for a next-generation neutrino telescope. Detailed measurements of deep-sea currents, light absorption and scattering lengths have underpinned the design of a multi-cubic-kilometre detector array. This facility, with advanced photon-detection modules and optimised geometry, is projected to achieve five-sigma sensitivity to known steady neutrino emitters within a single year of operation. By complementing existing Northern Hemisphere observatories, the planned deployment will enhance sky coverage and enable precise localisation of astrophysical neutrino sources, thereby advancing efforts to pinpoint the origins of cosmic rays and probe particle physics over cosmological baselines.

Astroparticle Physics and High-Energy Cosmic Phenomena publication trend

The graph below shows the total number of articles in astroparticle physics and high-energy cosmic phenomena across all publications each year (not limited to Nature Index journals).

Technical terms

Astroparticle physics: The interdisciplinary field studying elementary particles of astrophysical origin and their interactions in cosmic environments.

Cosmic rays: High-energy charged particles, primarily protons and atomic nuclei, accelerated in astrophysical sources and traversing interstellar space.

Neutrinos: Electrically neutral, weakly interacting leptons produced in nuclear and particle interactions, capable of traversing dense regions unimpeded.

Cherenkov radiation: Short pulses of light emitted when a charged particle moves faster than the phase velocity of light in a medium, used for particle detection.

Photohadronic interactions: Processes in which high-energy hadrons interact with photons, producing secondary particles such as pions that decay into neutrinos and gamma rays.

Multi-messenger astronomy: A coordinated observational approach that combines data from different cosmic messengers—photons, neutrinos, cosmic rays and gravitational waves—to study astrophysical sources.

References

1. TeV Neutrinos and Hard X-Rays from Relativistic Reconnection in the Corona of NGC 1068. The Astrophysical Journal Letters (2024).
2. A multi-cubic-kilometre neutrino telescope in the western Pacific Ocean. Nature Astronomy (2023).
3. THE GAMMA-RAY AND NEUTRINO SKY: A CONSISTENT PICTURE OF FERMI-LAT, MILAGRO, AND ICECUBE RESULTS. The Astrophysical Journal Letters (2015).
4. Measurement of the cosmic-ray energy spectrum above 2.5×1018 eV using the Pierre Auger Observatory. Physical Review D (2020).