Milestone results released by the Large High Altitude Air Shower Observatory (LHAASO) on November 16 have solved a decades-old mystery about the cosmic ray energy spectrum—which shows a sharp decrease in cosmic rays above 3 PeV, giving it an unusual knee-like shape.

The Large High Altitude Air Shower Observatory (LHAASO), a major national science and technology infrastructure project in China, has achieved a groundbreaking discovery in gamma-ray astronomy. Using over 1,200 days of observational data, LHAASO detected ultra-high-energy gamma-ray radiation from the tail region of the bow-shock pulsar wind nebula (BSPWN) associated with the pulsar PSR J1740+1000 with a significance of 17 standard deviations. This marks the first observation of gamma-ray radiation from the tail of a bow-shock pulsar wind nebula, challenging existing theories on particle transport mechanisms and suggesting the presence of a robust particle acceleration process in this region. The findings were published on February 7, 2025, in the academic journal The Innovation.

The Large High Altitude Air Shower Observatory (LHAASO) officially released the precise measurements of high-energy gamma radiation from the W51 complex, confirming it as a cosmic-ray accelerator boosting particles up to so-called ultra-high energies (UHE, above 1014 electronvolts). This study also provides key evidence about the cosmic-ray acceleration limit in this complex. The findings, entitled "Evidence for particle acceleration approaching PeV energies in the W51 complex," were published online in Science Bulletin on July 16. The research was conducted by the LHAASO International Collaboration, led by the Institute of High Energy Physics of the Chinese Academy of Sciences.

The Large High Altitude Air Shower Observatory (LHAASO) has accurately measured the cosmic ray all-particle energy spectrum and the mean logarithmic mass in the range of 0.3–30 peta-electronvolts (PeV). It has also discovered an “elbow” feature in the mean logarithmic mass spectrum of cosmic rays. The achievement, “Measurements of All-Particle Energy Spectrum and Mean Logarithmic Mass of Cosmic Rays from 0.3 to 30 PeV with LHAASO-KM2A,” was published online on March 26, 2024, as an “Editors’ Suggestion” and “Featured in Physics” letter in Physical Review Letters. This work was completed by the LHAASO international collaboration, which is led by the Institute of High Energy Physics (IHEP) of the Chinese Academy of Sciences. The corresponding authors of the letter are Dr. ZHANG Hengying and Prof. HE Huihai, both from IHEP, and Prof. FENG Cunfeng from Shandong University.

The Large High-Altitude Air Shower Observatory (LHAASO) officially published its first catalog of gamma-ray sources in the Astrophysical Journal Supplement Series on Feb. 27. The first LHAASO catalog contains 90 very-high-energy (VHE) gamma-ray sources, 32 of which are new VHE sources, significantly increasing the number of gamma-ray sources in the VHE band. It also contains 43 ultra-high-energy (UHE) gamma-ray sources, increasing the number of known UHE gamma-ray sources by three factors. UHE gamma-ray sources have become the best candidates for revealing the origin of cosmic rays. It is also revealed that pulsar wind nebulae are highly efficient UHE emitters in the Milky Way. Since the arXiv preprint version was released, more than 66 citations on inspire have accumulated. This work was carried out by the LHAASO Collaboration, with all four corresponding authors coming from the Institute of High Energy Physics of the Chinese Academy of Sciences, Dr. XI shaoqiang, Dr. HU shicong, Prof. CHEN songzhan and Prof. ZHA min.

The Large High Altitude Air Shower Observatory (LHAASO) has discovered a giant ultra-high-energy gamma-ray bubble structure in the Cygnus star-forming region, which is the first time in human history that the origin of cosmic rays with energy higher than 10 Peta-Electronvolt (PeV, 1PeV=1015eV) has been discovered. This achievement was officially published in the form of a cover article in Science Bulletin on Feb. 26, 2024. The research was completed by the LHAASO Collaboration led by Prof. CAO Zhen as the spokesperson from the Institute of High Energy Physics of the Chinese Academy of Sciences. Dr. GAO Chuandong, Dr. LI Cong, Prof. LIU Ruoyu and Prof. YANG Ruizhi are the co-corresponding authors of the paper.

In recognition of research groups or individuals who have completed or demonstrated significant achievements within the past five years, the Chinese Academy of Sciences (CAS) awarded the 2023 Outstanding Science and Technology Achievement Prize on Dec. 23, 2023. The research group of Large High Altitude Air Shower Observatory (LHAASO) was honored with the 2023 Outstanding Science and Technology Achievement Prize of CAS.

The Large High Altitude Air Shower Observatory (LHAASO) has officially released the precise energy spectrum for the highest-energy gamma-ray radiation from Gamma-Ray Burst (GRB) 221009A, the brightest GRB observed to date. This finding challenges the standard radiation model of GRB afterglows, revealing that the intensity of cosmic background light in the infrared band is lower than expected. Additionally, this measurement provides crucial information for examining Einstein’s special relativity theory and new physics, such as exploring axions as candidate particles for dark matter. The results were published by the LHAASO collaboration, which is led by the Institute of High Energy Physics of the Chinese Academy of Sciences, on Nov. 15 in Science Advances.

New research findings on the gamma-ray burst (GRB) named GRB 221009A from the Large High Altitude Air Shower Observatory (LHAASO) were published online by the journal Science on June 8, 2023. The study, entitled "A tera-electronvolt afterglow from a narrow jet in an extremely bright GRB 221009A", was completed by the LHAASO international collaboration.

The Large High Altitude Air Shower Observatory (LHAASO) project, one of China's major national scientific and technological infrastructure facilities, has successfully passed national acceptance and formally gone into operation. LHAASO is a facility focusing on cosmic ray observation and research. It was approved by the National Development and Reform Commission (NDRC) on Dec. 31, 2015. Jointly sponsored by the Chinese Academy of Sciences (CAS) and the People’s Government of Sichuan Province, the construction project was undertaken by the Chengdu Branch of CAS and the Institute of High Energy Physics (IHEP) of CAS. The construction of the main part of the facility began in 2017 and was completed in 2021. The LHAASO project passed an acceptance inspection by five professional teams organized by CAS that covered the following areas: technical performance, construction and installation, financial matters, equipment and assets, and records.