The Cherenkov Telescope Array or CTA is a multinational, worldwide project to build a new generation of ground-based

gamma-ray A gamma ray, also known as gamma radiation (symbol γ or \gamma), is a penetrating form of electromagnetic radiation arising from the radioactive decay of atomic nuclei. It consists of the shortest wavelength electromagnetic waves, typically sh ...

instrument in the

energy In physics, energy (from Ancient Greek: ἐνέργεια, ''enérgeia'', “activity”) is the quantitative property that is transferred to a body or to a physical system, recognizable in the performance of work and in the form of hea ...

range extending from some tens of

GeV GEV may refer to: * ''G.E.V.'' (board game), a tabletop game by Steve Jackson Games * Ashe County Airport, in North Carolina, United States * Gällivare Lapland Airport, in Sweden * Generalized extreme value distribution * Gev Sella, Israeli-Sou ...

to about 300 TeV. It is proposed as an open observatory and will consist of two arrays of Imaging Atmospheric Cherenkov telescopes (IACTs), a first array at the Northern Hemisphere with emphasis on the study of extragalactic objects at the lowest possible energies, and a second array at the Southern Hemisphere, which is to cover the full energy range and concentrate on galactic sources. The physics program of CTA goes beyond high energy astrophysics into

cosmology Cosmology () is a branch of physics and metaphysics dealing with the nature of the universe. The term ''cosmology'' was first used in English in 1656 in Thomas Blount's ''Glossographia'', and in 1731 taken up in Latin by German philosopher ...

and fundamental physics. Building on the technology of current generation ground-based gamma-ray detectors (

MAGIC Magic or Magick most commonly refers to: * Magic (supernatural), beliefs and actions employed to influence supernatural beings and forces * Ceremonial magic, encompasses a wide variety of rituals of magic * Magical thinking, the belief that unrela ...

HESS Hess or Heß may refer to: * Hess (surname), also ''Heß'' in German, people with the surname Hess * Hess, Oklahoma, a community in the United States * Hess Educational Organization, the largest private provider of English instruction in the Rep ...

, and

VERITAS Veritas is the name given to the Roman virtue of truthfulness, which was considered one of the main virtues any good Roman should possess. The Greek goddess of truth is Aletheia (Ancient Greek: ). The German philosopher Martin Heidegger argues ...

), CTA will be ten times more sensitive and have unprecedented accuracy in its detection of high-energy gamma rays. Current gamma-ray telescope arrays host up to five individual telescopes, but CTA is designed to detect gamma rays over a larger area and a wider range of views with more than 100 telescopes located in the northern and southern hemispheres. At least three classes of telescopes are required to cover the full CTA energy range (20 GeV to 300 TeV): Large-Sized Telescope (LST), Medium-Sized Telescope (MST) and Small-Sized Telescope (SST). The project to build CTA is well-advanced: prototypes exist for all the proposed telescope designs and significant site characterization and preparations are underway. An inter-governmental agreement for construction and subsequent operation of the observatory, a European Research Infrastructure Consortium (ERIC), is in preparation and the financial threshold is expected to be reached in 2019. The project was promoted to a Landmark on the road-map of the European Strategy Forum on Research Infrastructures (ESFRI), and is on the roadmaps for the European Astroparticle Physics network

ASPERA Aspera may refer to: Music * Aspera (band), an American indie rock band * ''(a)spera'', a 2009 album by Mirah * Above Symmetry, a Norwegian progressive metal band originally known as Aspera * "Aspera", the lead track from ''We Will Become Like Bir ...

and the European Astrophysics network

ASTRONET Astronet is a consortium which gather European funding agencies in order to establish a comprehensive long-term planning for the development of European astronomy. The consortium started on September 1, 2005. Participants *Centre national de ...

. The cost for base-line design of the project is estimated at (US$350 million). The network is scheduled to start collecting data in 2022.

CTA Consortium Members and CTAO Shareholders

As of December 2018, the CTA Consortium includes more than 1,420 members from 210 institutes in 31 countries: Armenia, Australia, Austria, Brazil, Bulgaria, Canada, Chile, Croatia, Czech Republic, Finland, France, Germany, Greece, India, Ireland, Italy, Japan, Mexico, Namibia, Netherlands, Norway, Poland, Slovenia, South Africa, Spain, Sweden, Switzerland, Thailand, the United Kingdom, Ukraine and the United States. The group of scientists and engineers are engaged in the scientific and technical development of CTA. Its internal authority, the Consortium Board, includes representatives from each of the Consortium institutes and is responsible for endorsing all major Consortium decisions. The CTA Observatory gGmbH (CTAO gGmbH) is the legal entity for CTA in the preparation of the implementation of the CTA Observatory. The CTAO gGmbH works in close cooperation with the CTA Consortium. The CTAO is governed by the CTA Council, composed of shareholders from 11 countries (Australia, Austria, Czech Republic, France, Germany, Italy, Japan, Slovenia, Spain, Switzerland, United Kingdom) and associate members from two countries (Netherlands and South Africa).

Array Sites

The site of the future Cherenkov Telescope Array

On 15 and 16 July 2015, the CTA decided to enter into detailed contract negotiations for hosting CTA on the European Southern Observatory (ESO)

Paranal Observatory Paranal Observatory is an astronomical observatory operated by the European Southern Observatory (ESO). It is located in the Atacama Desert of northern Chile on Cerro Paranal at altitude, south of Antofagasta. By total light-collecting area, it ...

in Chile and at the Instituto de Astrofisica de Canarias (IAC),

Roque de los Muchachos Observatory Roque de los Muchachos Observatory ( es, Observatorio del Roque de los Muchachos, ORM) is an astronomical observatory located in the municipality of Garafía on the island of La Palma in the Canary Islands, Spain. The observatory site is operated b ...

La Palma La Palma (, ), also known as ''La isla bonita'' () and officially San Miguel de La Palma, is the most north-westerly island of the Canary Islands, Spain. La Palma has an area of making it the fifth largest of the eight main Canary Islands. The ...

, Spain. On 19 September 2016, the Council of the Cherenkov Telescope Array Observatory (CTAO) concluded negotiations with the IAC to host CTA's northern hemisphere array at the Roque de los Muchachos Observatory in La Palma, Spain. On 19 December 2018, the final agreements were signed for the southern array to be hosted near the ESO's Paranal Observatory in northern Chile. CTA's southern hemisphere site is only 11 km southeast of the ESO's existing Paranal Observatory in the

Atacama Desert The Atacama Desert ( es, Desierto de Atacama) is a desert plateau in South America covering a 1,600 km (990 mi) strip of land on the Pacific coast, west of the Andes Mountains. The Atacama Desert is the driest nonpolar desert in th ...

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...

, which is considered one of the driest and most isolated regions on earth – a paradise for stargazers. CTA's northern hemisphere site is located on the existing site of the IAC's Roque de los Muchachos Observatory on the island of La Palma, the fifth largest island in the Canary Islands. At 2,200 metres altitude and nestled on a plateau below the rim of an extinct volcanic crater, the site currently hosts an operating gamma-ray observatory, the Major Atmospheric Gamma Ray Imaging Cherenkov (MAGIC) telescopes, as well as a wide variety of optical telescopes of various sizes.

Science

CTA will look at higher energy photons than ever measured before. In fact, the cosmic particle accelerators can reach energies inaccessible to human-made accelerators like the Large Hadron Collider. CTA will seek to understand the impact of high-energy particles in the evolution of cosmic systems and to gain insight into the most extreme and unusual phenomena in the Universe. CTA will search for annihilating

dark matter Dark matter is a hypothetical form of matter thought to account for approximately 85% of the matter in the universe. Dark matter is called "dark" because it does not appear to interact with the electromagnetic field, which means it does not a ...

particles and deviations from Einstein's theory of

special relativity In physics, the special theory of relativity, or special relativity for short, is a scientific theory regarding the relationship between space and time. In Albert Einstein's original treatment, the theory is based on two postulates: # The laws ...

and even conduct a census of

particle acceleration In a compressible sound transmission medium - mainly air - air particles get an accelerated motion: the particle acceleration or sound acceleration with the symbol a in metre/second2. In acoustics or physics, acceleration (symbol: ''a'') is def ...

in the Universe. Research at the CTA will seek to address questions in and beyond astrophysics. These questions fall under three major themes of study: Understanding the Origin and Role of Relativistic Cosmic Particles, Probing Extreme Environments, Exploring Frontiers in Physics. To address these themes, CTA will observe the following key targets:

Galactic Center The Galactic Center or Galactic Centre is the rotational center, the barycenter, of the Milky Way galaxy. Its central massive object is a supermassive black hole of about 4 million solar masses, which is called Sagittarius A*, a compact ra ...

, Large Magellanic Cloud, Galactic Plane, Galaxy Clusters, Cosmic Ray PeVatrons, Star Forming Systems,

Active Galactic Nuclei An active galactic nucleus (AGN) is a compact region at the center of a galaxy that has a much-higher-than-normal luminosity over at least some portion of the electromagnetic spectrum with characteristics indicating that the luminosity is not prod ...

, Transient Phenomena.

Access

Unlike current instruments, CTA will be operated as a proposal-driven open observatory. Observations will be carried out by observatory operators, then the data will be calibrated, reduced and, together with analysis tools, made available to the

principal investigator In many countries, the term principal investigator (PI) refers to the holder of an independent grant and the lead researcher for the grant project, usually in the sciences, such as a laboratory study or a clinical trial. The phrase is also often us ...

in FITS data format. After a proprietary period, data will be made openly available through the CTA data archive.

References

External links