On 24 June 2021, the Board of Governmental Representatives (BGR) approved the CTA Observatory’s (CTAO’s) Cost Book and Scientific & Technical Description, fundamental documents towards the establishment of the final legal entity of CTAO as a European Research Infrastructure Consortium (ERIC). The decision comes after the approval of the Cost Book by the CTAO Council this week. The BGR, comprised of representatives of the future ERIC member countries, is one of the key committees created to prepare and evaluate documentation for the transition of CTAO’s legal status from the current gGmbH (under German law) to an ERIC (under European law).

“The decision of the BGR endorses the support of the shareholder countries for the construction of the CTA Observatory,” explains Federico Ferrini, CTAO Managing Director. “We are very excited that the Cost Book and the Scientific & Technical Description evaluations were successfully completed and that the ERIC application will be finalised soon.”

The Cost Book approved by the BGR presents the expected construction costs for individual components and work items for building the CTA Observatory to which each country and institution will contribute.

“In preparing the Cost Book, we have taken great care in maximizing the science capabilities while aligning the scope of the construction project with the funding reality and strategic interests of the future ERIC members,” says Wolfgang Wild, CTAO Project Manager.

The CTAO’s Scientific & Technical Description presents the key aspects of CTAO, such as the construction project’s development and intended lifecycle, and summarizes the scientific capabilities and technical goals to be accomplished during the construction.

In particular, it includes the configuration of the telescope arrays at the two sites for the first construction phase, named “Alpha Configuration.” This configuration includes 4 Large-Sized Telescopes (LSTs) and 9 Medium-Sized Telescopes (MSTs) for the northern hemisphere array located on La Palma (Spain), and 14 MSTs and 37 Small-Sized Telescopes (SSTs) for the southern hemisphere array situated in the Atacama Desert (Chile). The definition of these configurations is the result of a meticulous optimization process for each array’s scientific capabilities, which implies the specialization of the northern array in extragalactic sources (low and medium CTAO’s energy range) and that of the southern array in Galactic targets (medium and high CTAO’s energy range) for the first construction phase.

“The Alpha Configuration ensures the outstanding performance of the Observatory and its transformational science,” says Roberta Zanin, CTAO Project Scientist. “Both telescope arrays will achieve 5 to 10 times better sensitivity than any current instrument, which will constitute a giant scientific leap in gamma-ray astronomy.”