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Cherenkov Telescope Array: Infrastructure Development and Start of Implementation

Periodic Reporting for period 2 - CTA-DEV (Cherenkov Telescope Array: Infrastructure Development and Start of Implementation)

Okres sprawozdawczy: 2017-01-01 do 2019-12-31

The Cherenkov Telescope Array project aims to provide a unique global facility for very high energy gamma ray astronomy, addressing many long-unanswered questions in astronomy and astrophysics, astro-particle physics, particle physics, and cosmology. Two arrays of Cherenkov telescopes – one in each hemisphere – will provide unprecedented sensitivity for the study of the Universe at the highest energies of the electromagnetic spectrum. The project is supported and promoted by the CTA Consortium, carried by over 200 institutes in 31 countries; Consortium institutes plan to provide the telescopes as in-kind contributions. The CTA Consortium provided instrument specifications and the design as a result of the CTA Preparatory Phase.

In 2013, Reviews by ESFRI have identified the main bottlenecks towards implementation of CTA as: characterization and survey of array sites; design and implementation of site infrastructure; concluding long-term agreements; and preparing for construction to begin.
The CTA-DEV project targeted these bottlenecks by specifically addressing: (i) Designing and planning in detail the site-specific infrastructure required to operate the telescopes provided by CTA Consortium institutes; (ii) Planning the deployment process, exercising it on the first telescopes and their infrastructure, and providing a solid foundation for the mass deployment of telescopes; (iii) Providing the legal basis for approval and deployment of CTA by creating the required founding agreement, hosting agreements, and framework contracts; (iv) Implementing local outreach programs in the host countries and defining the outreach infrastructure required, promoting relations with the host country at government, commercial, and public levels.

These tasks have been carried out by the CTA Observatory gGmbH (CTAO), a non-profit organisation founded by CTA member states to provide a legal framework for the preparation for the CTA Observatory, to administer CTA project management and system engineering, and to prepare for deployment.

During CTA-DEV project, two major resolutions were approved by the CTAO Council:
• The CTA South Site will be hosted by ESO at Paranal Observatory
• The final Legal Entity for the CTA Observatory will be a European Research Infrastructure Consortium (ERIC), entitled of the observatory construction and operation.
The two undertakings had significant impact on the progress of CTA-DEV, leading to resettlement of milestones, in some cases.

On the overall, the CTA-DEV project sustained the CTA Construction project in a decisive and delicate phase, providing inputs and contribution, both to technical and legal side.

It is worthy to underline that CTA Observatory will be the first ground-based gamma-ray observatory open to the worldwide astronomical and particle physics communities as a resource for data from unique, high-energy astronomical observations. The extent of the countries involved at various levels in the construction project, and its set up as an ERIC are substantially contributing to strengthen the ERA position in the global research landscape.
CTA-DEV activities mainly concern design of infrastructure and legal agreements towards transitioning to the construction phase of CTA. The major achievements are:

Infrastructure Design and Planning:
- Identification of the array sites – at ESO, Chile and La Palma, Spain – and of the exact array locations.
- Enhanced site characterization, especially of atmospheric parameters necessary to define in-depth design and calibration requirements
- Enhanced Reliability, Maintainability and Serviceability analysis of all system components to establish final requirements for infrastructure construction.
- A layout of access road networks, grid power connections, power and data distribution systems, and of operations and support buildings for the larger southern installation has been defined, and is being adapted for the smaller northern site.
- Commissioning of detailed design plans of the required infrastructure
- Preparation of major sub-contracts to evaluate site geology in order to finalize the detailed technical design planning before start of infrastructure construction
- Fine-tuning of telescope positions

Infrastructure Deployment:
- The model for maintenance and operations in particular of the larger southern site was updated and improved in interaction with ESO, reflecting the planned mode of operation and local specifics.
- A deployment plan for CTA south was set up and approved as part of the ESO Hosting Agreement by CTA as well as ESO Council.
- Maintenance and Operations Models were significantly refined using RAM and Requirement analysis
- After the signature of the southern site hosting agreement the execution of the deployment plan is being prepared with first steps on the southern site ongoing after the Site Manager took office and the necessary procurement, logistics and personnel procedures are in place.

Legal agreements for setting up the observatory:
- Preparation and signature of the hosting agreements for the Northern and Southern CTA sites
- A Memorandum of Understanding on the construction and operation of CTA
- An In-kind contribution scheme was prepared and approved by Council
- The locations for CTAO Headquarters (Bologna/Italy) and CTA Science Data Management Centre (Zeuthen/Germany) were chosen by Council; setup of the facilities is either finished or ongoing.
- A European Research Infrastructure Consortium was chosen as the final legal entity for the Observatory.
- Working procedures and regulations for operating the southern site were prepared and are established for the southern site together with the European Southern Observatory.

Infrastructure for outreach and host-country stakeholder management:
- A communications plan was developed, identifying the communications objectives, the stakeholders to be addressed, the communications strategy and the themes and key messages.
- As a first implementation step, a new dramatically improved web presence for CTA has been created
- Facebook, Twitter and Flickr feeds are being served.
- The Chile-specific outreach infrastructure requirements were defined and are now being implemented after the final signature of the hosting agreement.
CTA-DEV is an essential step towards realizing CTA. Once operational, CTA will advance the state of the art in many aspects:
(i) Worldwide integration: CTA for the first time brings together the experience of groups worldwide working in gamma-ray astronomy at very high energies.
(ii) Performance of the instrument: CTA will provide full-sky coverage, with unprecedented sensitivity, spectral coverage, angular resolution, energy resolution, and timing resolution. CTA will improve performance by an order of magnitude over existing instruments.
(iii) Operation as an open observatory: CTA will, for the first time in this field, be operated as a true observatory, open to a wide scientific community and providing support for easy access and analysis of data. Data will be made publicly available and will be accessible through the Virtual Observatory.
And (iv) Technical implementation, operation, and data access: While based on existing and proven techniques, the goals of CTA imply significant advances in terms of efficiency of construction and installation, in terms of the reliability of the telescopes, and in terms of data preparation and dissemination.
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Artistic rendering of the southern CTA site