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'{{Short description|Cosmic ray observatory in China}} The '''Large High Altitude Air Shower Observatory''' ('''LHAASO''') is a [[gamma-ray]] and [[cosmic-ray observatory]] in [[Daocheng County|Daocheng]], in the [[Garzê Tibetan Autonomous Prefecture]] in [[Sichuan]], China. It is designed to observe [[air shower (physics)|air shower]]s triggered by [[gamma rays]] and [[cosmic rays]].<ref>{{Cite journal|last1=Vernetto|first1=S|last2=LHAASO Collaboration|date=May 2016|title=Gamma Ray Astronomy with LHAASO|journal=Journal of Physics: Conference Series|volume=718|issue=5|pages=052043|doi=10.1088/1742-6596/718/5/052043|bibcode=2016JPhCS.718e2043V|issn=1742-6588|doi-access=free}}</ref> The observatory is at an altitude of {{convert|4410|m|ft}} above sea level.<ref>{{Cite arXiv|last1=Zhu|first1=H.|last2=Zhu|first2=F. R.|last3=Zhou|first3=X. X.|last4=Zhao|first4=Y.|last5=Zhang|first5=X.|last6=Zhang|first6=S. S.|last7=Zhang|first7=M. F.|last8=Zhang|first8=L.|last9=Zhang|first9=B.|date=2019-05-07|title=The Large High Altitude Air Shower Observatory (LHAASO) Science White Paper|class=astro-ph.HE|eprint=1905.02773v1}}</ref> Observations started in April 2019.<ref>{{Cite journal|last=Cyranoski|first=David|date=2019-05-08|title=China's mountain observatory begins hunt for origins of cosmic rays|url=http://www.nature.com/articles/d41586-019-01467-1|journal=Nature|doi=10.1038/d41586-019-01467-1|pmid=32376923|s2cid=165029766}}</ref> The observatory covers an area of some {{convert|145|ha|acre}}. It has three underground observing pools, each “more than triple the size of the [[Water Cube]] (National Aquatic Center) in [[Beijing]]”. One of the pools is designed to contain {{convert|100000|tonne|ton}} of water. The pools will contain 12 telescopes to capture high-energy photons. [[Cherenkov radiation]] detectors are used. Research teams from [[Australia]] and [[Thailand]] will participate in the project directly, with others expressing interest.<ref name=”2019-10-24_SD”>[http://www.spacedaily.com/reports/Chinese_scientists_pursuit_of_cosmic_rays_opens_windows_on_universe_999.html Chinese scientists' pursuit of cosmic rays opens windows on universe], [SpaceDaily.com], 2019-10-24</ref> The observatory works essentially as the [[Chicago Air Shower Array|CASA-MIA]] observatory did but with a bigger surface array, better muon detectors, improved designed layout and at higher altitude.<ref>{{Cite web|last=Xin|first=Ling|title=Highest-Energy Particles Yet Arrive from Ancient Crab Nebula|url=https://www.scientificamerican.com/article/highest-energy-particles-yet-arrive-from-ancient-crab-nebula/|access-date=2021-07-14|website=Scientific American|language=en}}</ref> == Scientific results == On 17 May, 2021, LHAASO Discovers a Dozen PeVatrons and Photons Exceeding 1 PeV including one at 1.4 PeV.<ref name="Physics 2021">{{cite web | last=Physics | first=Institute of High Energy | title=LHAASO Discovers a Dozen PeVatrons and Photons Exceeding 1 PeV and Launches Ultra-High-Energy Gamma Astronomy Era ----Institute of High Energy Physics | website=english.ihep.cas.cn | date=2021-05-18 | url=http://english.ihep.cas.cn/doc/4233.html | archive-url=https://web.archive.org/web/20220120083742/http://english.ihep.cas.cn/doc/4233.html | archive-date=2022-01-20 | url-status=dead | language=zh | access-date=2022-10-17}}</ref><ref>{{Cite journal|author1=Cao, Z.|author2= Aharonian, F.A.|author3= An, Q. |display-authors=etal|date=2021-05-17|title=Ultrahigh-energy photons up to 1.4 petaelectronvolts from 12 γ-ray Galactic sources|url=https://www.nature.com/articles/s41586-021-03498-z|journal=Nature|volume= 594|issue= 7861|pages= 33–36|doi=10.1038/s41586-021-03498-z|pmid= 34002091|bibcode= 2021Natur.594...33C|s2cid= 234768604}}</ref> 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.<ref>{{Cite journal |last=LHAASO Collaboration |date=2024-02-26 |title=An ultrahigh-energy γ-ray bubble powered by a super PeVatron |url=https://www.sciencedirect.com/science/article/pii/S209592732300912X |journal=Science Bulletin |volume=69 |issue=4 |pages=449–457 |doi=10.1016/j.scib.2023.12.040 |issn=2095-9273}}</ref><ref>{{Cite web |last=Sciences |first=Chinese Academy of |title=LHAASO discovers giant ultra-high-energy gamma-ray bubble, identifying the first super PeVatron |url=https://phys.org/news/2024-02-lhaaso-giant-ultra-high-energy.html |access-date=2024-02-26 |website=phys.org |language=en}}</ref><ref>{{Cite web |last=Times |first=Global |title=Chinese researchers confirm origin of cosmic rays for the first time - Global Times |url=https://www.globaltimes.cn/page/202402/1307716.shtml |access-date=2024-02-26 |website=www.globaltimes.cn}}</ref> == See also == * [[List of astronomical observatories]] * [[High Altitude Water Cherenkov Experiment]] == References == {{Reflist}} {{coord|29|21|31|N|100|08|15|E|type:landmark_region:CN|display=title}} {{Portal bar|China|Astronomy|Stars|Spaceflight|Outer space|Solar System|Education|Science}} [[Category:Cosmic-ray telescopes]] [[Category:Astronomical observatories in China]] {{Observatory-stub}} {{China-stub}}'