On 10 April 2014, the 12 country delegates mandated by their governments to decide about the start of site negotiations for the Cherenkov Telescope Array (CTA) met in Munich. They took note of the report of the international Site Selection Committee (SSC) and thanked the members of the SSC as well as the CTA consortium for their extensive inputs on the merits of the proposed sites.

The delegates representing Argentina, Austria, Brazil, France, Germany, Italy, Namibia, Poland, Spain, South Africa, Switzerland and the UK decided, based on the 75% majority required, to start the negotiations on the two sites in the southern hemisphere, namely Aar in Namibia and the European Southern Observatory (ESO) in Chile, keeping Leoncito in Argentina as a third option. After negotiations finally one site will be selected at the end of the year. With the selection of the potential telescope sites in the southern hemisphere an important step towards the realization of the international Cherenkov Telescope Array has been made.

As far as the northern site of the CTA Observatory is concerned — candidate sites are located in Mexico, Spain and the USA — further considerations are necessary. Therefore, the delegates decided to postpone their decision and to ask the CTA board of agency representatives — the Resource Board — to take this forward. The decision for the negotiations about the northern hemisphere site will be taken as soon as possible.

“We are very happy that this important step has been reached” said B. Vierkorn-Rudolph, chair of the CTA Resource Board. “CTA will be a unique large-scale infrastructure for astronomy — with this decision we now can start the negotiations with the potential site countries in the southern hemisphere and advance the implementation of CTA.” The spokesperson of the CTA Consortium, Professor Werner Hofmann said “The site choice is on the critical path towards implementing CTA; this decision represents a major step forward and we appreciate very much the engagement and support of the funding agencies and the country delegates involved in the decision.”

CTA — the Cherenkov Telescope Array (http://www.cta-observatory.org) — is a multinational, world-wide project to construct a unique instrument exploring the cosmos at the highest photon energies. Over 1,000 scientists and engineers from 5 continents, 28 countries and over 170 research institutes participate in the CTA project. CTA will provide an order-of-magnitude jump in sensitivity over current instruments, providing novel insights into some of the most extreme processes in the universe. CTA will consist of over 100 Cherenkov telescopes of 23-m, 12-m and 4-m dish size located at one site in the southern and a smaller site in the northern hemisphere. Potential candidate sites have been identified in the northern and southern hemispheres. Extensive studies of the environmental conditions, simulations of the science performance and assessments of costs of construction were conducted. The Site Selection Committee, composed of international experts in the evaluation of sites for astronomical observatories, has reviewed the studies and provided an independent assessment of the various candidate sites.

Contacts:
Prof. W. Hofmann
CTA Spokesperson
+49 622 151 6330

Prof. S. Wagner
CTA Project Office
+49 622 154 1712

Dr. B. Vierkorn-Rudolph
Chair CTA Resource Board
+49 228 9957 3633

Dr. G. Vettolani
Co-Chair CTA Resource Board
+39 063 553 3360

APPEC (http://www.appec.org), the Astroparticle Physics European Consortium, brings together national government agencies and institutes responsible for coordinating and funding national research efforts in Astroparticle Physics.