The Large High Altitude Air Shower Observatory (LHAASO) is a

gamma-ray A gamma ray, also known as gamma radiation (symbol ), is a penetrating form of electromagnetic radiation arising from high energy interactions like the radioactive decay of atomic nuclei or astronomical events like solar flares. It consists ...

and cosmic-ray observatory in Daocheng, in the

Garzê Tibetan Autonomous Prefecture Garzê Tibetan Autonomous Prefecture, often shortened to Ganzi Prefecture, is an autonomous prefecture in the western arm of Sichuan province, China bordering Yunnan to the south, the Tibet Autonomous Region to the west, and Gansu to the north ...

Sichuan Sichuan is a province in Southwestern China, occupying the Sichuan Basin and Tibetan Plateau—between the Jinsha River to the west, the Daba Mountains to the north, and the Yunnan–Guizhou Plateau to the south. Its capital city is Cheng ...

, China. It is designed to observe air showers triggered by

gamma rays A gamma ray, also known as gamma radiation (symbol ), is a penetrating form of electromagnetic radiation arising from high energy interactions like the radioactive decay of atomic nuclei or astronomical events like solar flares. It consists o ...

and

cosmic rays Cosmic rays or astroparticles are high-energy particles or clusters of particles (primarily represented by protons or atomic nuclei) that move through space at nearly the speed of light. They originate from the Sun, from outside of the Solar ...

. The observatory is at an altitude of above sea level. Observations started in April 2019. The observatory covers an area of some . It has three underground observing pools, each “more than triple the size of the Water Cube (National Aquatic Center) in

Beijing Beijing, Chinese postal romanization, previously romanized as Peking, is the capital city of China. With more than 22 million residents, it is the world's List of national capitals by population, most populous national capital city as well as ...

”. One of the pools is designed to contain of water. The pools will contain 12 telescopes to capture high-energy photons.

Cherenkov radiation Cherenkov radiation () is electromagnetic radiation emitted when a charged particle (such as an electron) passes through a dielectric medium (such as distilled water) at a speed greater than the phase velocity (speed of propagation of a wavefro ...

detectors are used. Research teams from

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and

Thailand Thailand, officially the Kingdom of Thailand and historically known as Siam (the official name until 1939), is a country in Southeast Asia on the Mainland Southeast Asia, Indochinese Peninsula. With a population of almost 66 million, it spa ...

will participate in the project directly, with others expressing interest.Chinese scientists' pursuit of cosmic rays opens windows on universe
paceDaily.com 2019-10-24 The observatory works essentially as the CASA-MIA observatory did but with a bigger surface array, better muon detectors, improved designed layout and at higher altitude.

Scientific results

By 2021, LHAASO has discovered a dozen ultra-high-energy cosmic accelerators within the Milky Way (PeVatrons) and detected photons with energies up to 1.4 PeV. On 26 February, 2024, LHAASO reported the discovery of "a giant ultra-high-energy gamma-ray bubble structure in the Cygnus star-forming region." It contains multiple photons exceeding 1 PeV and at least one reaching 2.5 PeV, leading scientists to identify the presence of a "super cosmic ray accelerator" within the structure.

References

{{Portal bar, China, Astronomy, Stars, Spaceflight, Outer space, Solar System, Education, Science Cosmic-ray telescopes Astronomical observatories in China

Scientific results

See also

References