ESCAPE

The CTAO is a member of ESCAPE, an alliance formed by several research infrastructures and organisations across astronomy, astrophysics, particle and nuclear physics. ESCAPE is one of the five science clusters that exist as part of the European Open Science Cloud (EOSC). Within the ESCAPE Collaboration, the members work together on common challenges to find solutions in the areas of large-scale data management, data processing and analysis in support of open data and research. The collaboration aims to promote open science and FAIR (Findable, Accessible, Interoperable and Reusable) principles. Developing common approaches will provide the science communities with potential for new science and scientific discoveries across the boundaries of infrastructures, research domains and wavelengths.
The foundations of the ESCAPE Collaboration rest on the ESCAPE Project (European Science Cluster of Astronomy & Particle physics ESFRI research infrastructures, 2019-2023) which brought together 31 partners from eight countries to support the implementation of various aspects of an EOSC for astronomy and astroparticle and particle physics according to FAIR principles.
Members of the CTAO Central Organisation and the CTAO Consortium participated in all of the work packages leading to important developments and testing of the CTAO use cases in real world environments, which are now being used further in the CTAO project.
IVOA

Bringing together multiple independent research infrastructures, providers of data, software and services, as well as users from various domains, requires the establishment of commonly agreed and accepted standards and recommendations. This approach aims to create a coherent and interoperable landscape where resources, applications, and communities can collaborate seamlessly.
This is the vision of the Virtual Observatory (VO), and its International Virtual Observatory Alliance (IVOA) established in June 2002, through which the astronomical datasets and services are connected as a whole. The IVOA encourages observatories, universities and astronomy projects worldwide to become involved in the VO, promotes the related standards and its applications, and educates the user community on its usage.
One of the main pillars of the CTAO’s science program is multi-wavelength and multi-messenger astrophysics, which relies on the capability of the scientists to easily combine information from several experiments in a joint analysis. The CTAO aims to enable its users to make new science discoveries by supporting the interoperability of the high-level science data and science analysis tools, the science platforms and science archives, science alert streams and by implementing FAIR principles and VO standards. In addition, the CTAO Central Organisation and members of the CTAO Consortium are active participants in the IVOA meetings and working groups to help shape or extend the VO standards to accommodate high-energy astronomy and CTAO use cases. In 2024, members of the CTAO collaborated with other high- and very-high energy observatories and instruments to establish the High Energy Interest Group (HEIG) to address the current and future needs of high- and very high-energy astrophysics by supporting their integration into the IVOA framework.
SKAO

In 2020, the CTAO and the SKAO engaged in closer collaboration under a Memorandum of Understanding (MoU) that facilitates greater sharing of knowledge and expertise in areas including engineering, science, technology and administration.
The SKAO is a next-generation radio astronomy-driven Big Data facility that will revolutionise the understanding of the Universe at the lowest wavelengths. With the increasing importance of multi-wavelength astronomy, joint observations between the SKAO and the CTAO, covering the low and high edge of the electromagnetic spectrum, respectively, will be key to unveiling a completely new view of the Universe. There are exciting areas of synergy between the observatories: both radio and gamma rays are a probe of the violent and variable Universe, turning them into fundamental messengers for the study of active galactic nuclei, transient events such as gamma-ray bursts and fast radio bursts, accretion into compact objects and gravitational wave counterparts.
VODF

The CTAO is an active member of the Very-high-energy Open Data Format (VODF) working group, which aims to create an open data model and format for very high-energy (VHE) gamma-ray and neutrino astronomy, with consideration to IVOA standards. The primary objective of VODF is to establish a uniform collection of file formats and standards for data from the lowest-level (events lists) to higher-level products (such as sky images, light curves or spectra). By adhering to these standards, researchers can employ available common scientific tools to analyze data obtained from various high-energy instruments.