Free Astronomy Magazine March-April 2019

MARCH-APRIL 2019 T his aerial view shows beautifully the Chilean Atacama Desert around the ESO Paranal Observatory, home to the Very Large Telescope (seen at the bottom right). Close to the VLT, one can see the dome of the VISTA survey telescope, and to the right, the Paranal Residence and basecamp. The peak in the distance is the 6739-metre high volcano be- longing to the Andes, Llullaillaco. Also in the image, to the middle left, one can see an isolated peak with a curvy road leading to its summit. vThis is Cerro Armazones, the se- lected home for the future European Extremely Large Telescope (E-ELT). [ESO/M. Tarenghi] stone in the fast-growing era of multi-messenger astrophysics, pro- viding an opportunity for further collaboration with other large in- frastructures, such as the Atacama Large Millimeter/submillimeter Array (ALMA), the Square Kilometre Array (SKA) and state-of-the-art gravita- tional-wave interferometers.” Current Cherenkov telescope arrays, sensitive to very high-energy gamma rays, consist of only a handful of in- dividual telescopes, but CTA — with its larger collecting area and excel- lent angular resolution — will be the largest and most sensitive array of gamma-ray telescopes in the world. It will detect gamma rays with unprecedented accuracy and will be 10 times as sensitive as any of its predecessors. Although the Earth’s atmosphere prevents gamma rays from reaching the surface, CTA’s mirrors and high- speed cameras will capture the short-lived flashes of the eerie blue Cherenkov radiation produced when gamma rays interact with Earth’s atmosphere. By detecting this Cherenkov light, scientists will be able to trace the gamma ray back to its cosmic source. The scientific scope of CTA is ex- tremely broad: from understanding the role of relativistic cosmic parti- cles to the search for dark matter. CTA will explore the extreme Uni- verse, probing environments from the immediate neighbourhood of black holes to the cosmic voids on the largest scales. It may even lead to brand new physics as it studies the nature of matter and forces be- yond the standard model. CTA will operate across two sites, one in each hemisphere, allowing it to maximise its coverage of the night sky. When construction is complete, the CTAO will comprise 19 telescopes in the northern hemi- sphere — located at the Observato- rio del Roque de los Muchachos on the island of La Palma in the Canary Islands — and 99 telescopes in the southern hemisphere. More than 1400 scientists and engi- neers from countries across five con- tinents are engaged in the scientific and technical development of CTA. The shareholders of the current legal entity — CTAO gGmbH — are the representatives of ministries and funding agencies from Aus- tralia, Austria, the Czech Republic, France, Germany, Italy, the Nether- lands, Japan, Slovenia, South Africa, Spain, Switzerland and the United Kingdom. They are currently pre- paring for the establishment of a European Research Infrastructure Consortium — the CTAO ERIC — which will then construct the im- mense observatory. The ERIC will be composed of CTAO's Member States and associated countries. !