Research Groups

The Center for Theoretical Astrophysics & Cosmology (CTAC) has a diverse research program:

High performance computing

In astrophysics, perhaps even more so than in other scientific disciplines, there is an intimate interdependency between theoretical research, which is overwhelmingly reliant on simulations and modelling, and the exploitation of data from large observational facilities. In Zurich we fill this important methodological gap using simulations and modelling which, due to the intrinsic complexity of astrophysical phenomena, requires the most advanced computational infrastructure. In Zurich we develop and maintain a variety of state of the art parallel astrophysics simulation codes, visualisation tools and analysis software. We also design and maintain high end supercomputing facilities, such as the ZBOX and GPU clusters.


One of the major activities at CTAC is to perform N-body simulations of the universe as a whole, in order to predict theoretically the statistical properties of the distribution of matter in the universe. These simulations are performed using two codes developed at the University: PKDGRAV (main author Stadel) and Ramses (main author Teyssier). Launching in 2020, ESA's Cosmic Vision 2015-2025 identifies Euclid as its premier cosmology mission. Our activity is playing a very central role in the preparation and the anticipated data analysis of Euclid. Prof. Teyssier is coordinating the Cosmological Simulation Working Group of the Euclid Consortium. Prof. Moore is the PI at the University of Zurich of a Sinergia SNF proposal on Euclid Science (PI Meylan).

Dark Matter

CTAC members have a very strong research program in modelling the clustering properties of dark matter. Prof. Moore and Dr. Stadel have been leading the international competition in computing the detailed structure of dark matter haloes, in particular the dark halo of our own Milky Way.  Notable results include the prediction of dark matter substructure that extends 15 decades in mass to Earth-mass structures.  Prof. Lake has also discovered recently the possibility of forming within the Milky Way a dark disk, significantly altering our understanding of the velocity structure of dark matter particles. These results are frequently used to test candidates for the dark matter particle and to guide experimental searches that aim to detect the dark matter via direct and indirect detection. We have strong links in this area to the research group of Prof. Baudis.

Galaxy formation

The University of Zurich hosts one of the world leading groups in galaxy formation theory. Profs. Lake, Moore, Teyssier and Mayer have contributed significantly to our understanding of how galaxies form and in the origin of the Hubble sequence of galaxies. Notable results include the first numerical studies of disk galaxy formation that could match the properties of Milky Way type galaxies and new models for the origin of galaxy morphologies across the Hubble sequence. Prof. Teyssier and Prof. Mayer have studied in great details the role of supermassive black holes in shaping massive elliptical galaxies. Prof. Mayer has studied also supermassive black holes collisions, with important consequences on the detectability of gravitational waves. This expertise in the role of baryonic processes during structure formation is one of the most innovative aspects of CTAC research.

Planetary sciences

The origin and evolution of planetary systems is a major research activity at CTAC. Prof. Helled is involved in various space missions including missions to explore Jupiter (Juno) and its satellite system (JUICE), and space missions aimed to characterise exoplanets (PLATO, ARIEL). Prof. Mayer and collaborators are leaders in the area of giant planet formation and the early evolution of dusty proto-planetary disks. Prof. Moore & Stadel have an extensive research program on the formation history of Earth-like planets, the diversity and characteristics of exoplanetary systems and implications for astrobiology such as the delivery of carbon and water into habitable zones. Prof. Moore is PI of the UZH activities within a newly established National Centres of Competence in Research (NCCR) which joins together planetary research activities across Switzerland. Central to our research is the newly developed GPU code GENGA (author Stadel), which runs entirely on GPUs and can perform precise and fast calculations of the collisional formation and evolution of planets in the presence of gas disks.