Stars are the fundamental building blocks of galaxies and stellar clusters. They are often formed as part of small stellar systems, such as binaries and triples. Interactions between the stars give rise to some of the most energetic events in the universe and most exciting puzzles of modern astrophysics, e.g. supernovae Type Ia explosions, X-ray bursts, and gamma-ray bursts. Even though, the principles of binary evolution theory have been accepted for a long time, the evolution of triples is an uncharted territory. There is a need to understand the evolution of triples, as they are common and often invoked to explain compact and exotic binaries. The advents of large-scale surveys are currently providing us with an unprecedented number of stars, binaries and triples that can help us to improve our understanding of galactic structure and stellar evolution. However, the recent increase in observational work has not been matched by theoretical developments that are necessary for understanding these stellar populations. I propose to conduct the first consistent study of triple evolution in which stellar evolution and a full treatment of dynamics is taken into account simultaneously. The results will be compared directly with observations and this process will be iterated in order to provide a well-constrained model for triple evolution. It is an excellent moment to conduct this study as we finally have the tools and computer power to make a big leap forward in the modelling of the evolution of triple systems.

The Cherenkov Telescope Array (CTA) is one of the major future facilities of the field of astroparticle physics and high-energy astrophysics, dedicated to exploring the high-energy universe with γ-rays. Planned to start full operation by 2020, it will address important scientific topics, such as the origin of cosmic rays and their interaction with interstellar gas, the energetic output of accreting black holes and the existence of dark matter. CTA is a worldwide collaboration of more than 1000 scientists, and it is highly ranked in all the relevant US and European roadmaps (ASPERA, ASTRONET, ESFRI, etc), as well as in the Dutch astronomy and the new astroparticle physics roadmaps. This establishes γ-ray astronomy as a new area of activity in the Netherlands. The purpose of this proposal is to foster the Dutch CTA membership and provide the first share of CTA construction costs by building two full cameras for the small size telescopes of CTA. We are requesting funding equivalent to three research positions for an instrumental scientist, engineering resources, and equipment costs. The cameras will be designed, built, validated, and put into operation by the Universities of Amsterdam, Groningen, and Nijmegen, in close collaboration with our international partners. Such a hardware contribution, together with operational fees that are requested as part of the umbrella proposal by Hörandel, will promote the Netherlands from an observing to a full member country of CTA and will establish the access to the very first CTA data, which already promise exciting science results, for Dutch scientists.

The first direct detection of gravitational waves has opened up a new window to the Universe. With dozens of detections so far, and hundreds more coming, their sources are still heavily debated in the scientific community. Here we will investigate new and common pathways that involve multiple star systems, particularly three stars.