This article originally appeared in @TheU.
At the start of the year, the European Commission established the Cherenkov Telescope Array Observatory (CTAO) as a European Research Infrastructure Consortium (ERIC), furthering its mission to become the world’s largest and most powerful observatory for gamma-ray astronomy. The creation of the CTAO-ERIC will enable the observatory’s construction to advance rapidly and provide a framework for distributing its data worldwide, significantly accelerating its progress toward scientific discovery. On Feb. 13, 2025, the ERIC Council approved to immediately negotiate the establishment of Japan as a strategic partner and the United States, Brazil and Australia as third-party members.
“This field did not exist before 1989 when the first the gamma ray source was detected. At that point, we knew of four sources in the world,” said Dave Kieda, professor in the Department of Physics & Astronomy at the University of Utah and the CTAO spokesperson for the U.S. “The past 35 years, we went from detecting the first to now seeing several hundred. With CTAO, we’re going to see thousands. And the University of Utah is part of that legacy.”
The CTAO-ERIC was established with the international support of 11 countries and one intergovernmental organization that contributed to the technological development, construction and operation of the observatory. For Kieda, the new array will give astronomers an unprecedented view of the mysterious radiation he’s spent his career studying.
“Over the last decade, people have discovered that these high energy gamma rays are present in many, many types of very energetic astronomical phenomenon, but we don’t know much about where they come from,” Kieda said.
Think about it this way, he explained. The stars you can see with your eyes in the sky follow a predictable, rather uneventful existence for most of their lifetime. They burn hydrogen for a long time, then eventually run out of fuel and explode as a supernova.
“We’re looking at what comes after a star exhausts its life,” Kieda continued. “It turns out, these high energy gamma rays have massive consequences for the fate of our galaxy in terms of how stars are formed, where galaxies evolve, and what other hidden energies and matter could be out there that determine whether the universe will eventually collapse or continuously expand forever.”
Kieda’s research group led the design and construction of key hardware for the medium-sized telescopes (MSTs) in the CTAO array, integrating technology he previously developed for the VERITAS (Very Energetic Radiation Imaging Telescope Array System) experimental observatory and for the new ultra-high resolution gamma ray Schwarzchild-Couder Telescope. Before CTAO, VERITAS was the world’s most sensitive very-high-energy-gamma-ray observatory that could detect brief flashes of the blue “Cherenkov” light, created as the gamma rays hit the Earth’s atmosphere.
VERITAS operated for nearly two decades at the Whipple Observatory in Amado, Arizona. Over that time, Kieda designed and built crucial technology at the U with the help of dozens of graduate and undergraduate students. The CTAO array will be up to 20 times more sensitive than VERITAS and may solve the mystery of where the gamma rays originate.
“We’ve actually seen higher energy emissions that anybody ever anticipated. We’ve seen many diverse places produce this radiation. We’ve just started to scratch the surface on where this stuff comes from,” he said. “With the new sensitivity, we expect to see gamma rays emitted in coincidence with gravitational waves and neutrinos.
The ERIC not only provides the central organisation with a formal framework to accept and operate the current telescope prototypes, but it also allows for the initial start of construction for an eventual full array of more than 60 telescopes across both telescope sites in Spain and Chile. On the CTAO-North site, where the Large-Sized Telescope prototype (LST-1) is under commissioning, three additional LSTs and one MST are expected to be built in the next 1-2 years. Meanwhile, on the CTAO-South site, the first five Small-Sized Telescopes (SSTs) and two MSTs are expected to be delivered by early 2026. Thus, with the aid of the ERIC, the observatory is expected to be able to operate intermediate array configurations as early as 2026. These sub-sets of the final arrays will already be more sensitive than any existing instrument, bringing the observatory’s early science within reach.
The impact of the ERIC will extend beyond hardware, influencing several other key areas. In the coming months, the observatory will prepare to integrate and operate advanced software designed to control the telescopes and their supporting devices on-site, as well as to manage data processing.
“The ERIC status strengthens the presence of the CTAO in Europe and its role as a key player in the European Research Area, but the support we have received and the scope of the CTAO ERIC’s influence goes far beyond European borders,” explained Prof. Federico Ferrini, co-Managing Director. “To build and operate the world’s largest gamma-ray observatory that serves the ambitious needs of the global scientific community, we are counting on an increasing number of partners from around the world.”
The Commission Implementing Decision (EU) officially establishing the Cherenkov Telescope Array Observatory–European Research Infrastructure Consortium (CTAO–ERIC) is available on the Official Journal of the European Union.
Adapted from a release by CTAO.