Working the case of the mysterious supermassive black holes Supermassive black holes have today at least a million times the mass of our Sun, but we know that they were born small in the infancy of the Universe: the mystery is how. This project looks at the lighter ones— those that grew less than the others — to more directly find clues on their origin. I exploit the light coming from the disrupted stars, that these baby giants rapaciously eat, combining state of the art simulations and the wealth of current data.

Two major pursuits in modern theoretical astronomy concern pinning down the cosmology of our Universe and understanding how galaxies form. We have advanced to the point where these two topics can no longer be considered separately, and a full understanding of either requires the intricate link between galaxy formation and cosmology to be understood. This is becoming increasingly pressing, as ongoing and upcoming surveys such as DES, LSST, Euclid and WFIRST rely on our (as of yet incomplete) understanding of how galaxies redistribute matter, in order for their measurements to be interpreted correctly. One of the main goals of these surveys is to derive the parameters of our Universe to very high precision by precisely measuring the distribution of matter, which is extremely sensitive to cosmology. To fully exploit these observations, theoretical models are needed that can predict the clustering of matter, as a function of cosmology, to 1% or better. Currently, these models do not exist. While models based on a Universe containing only dark matter can satisfy this requirement, the real Universe contains galaxies and all the energetic processes that come with it, and these have been shown to redistribute matter on large scales in ways that are not yet completely understood. Ignoring these processes will lead us to wrongly infer the properties of our Universe. I propose to build a new model that incorporates the effects that galaxies have on the distribution of matter to prepare us for upcoming surveys, by combining data from a great many existing and upcoming numerical simulations. This is the perfect time for this research due to the advances in simulating galaxy formation over the last several years and the imminence of massive amounts of data that will be wasted or wrongly interpreted without a better model for the clustering of matter.

This project aims at discovering asteroids by mining existing JWST mid-infrared images from the James Webb Space Telescope (JWST). This has a major impact in two fields: the origin and evolution of the Solar System and the defence of planet Earth. JWST Mid-Infrared Instrument (MIRI) images provide unprecedented precision and resolution at wavelengths where the thermal emission of asteroids peak. Millions of images are being taken serendipitously in MIRIs science programs, a gold mine to search for new asteroids.

Since 2009 Simon Portegies Zwart leads an interdisciplinary research team on Computational Astrophysics at the Sterrewacht Leiden (CAstLe). This team is currently composed of 1 software engineer, 2 postdoctoral researchers, 6 PhD students and 4 MSc students. The aim of this team is to study the universe by means of simulation. The specific areas of research in astrophysics include the evolution of exotic planetary systems, the evolution of binary (and higher order multiple) stars, and the dynamical evolution of dense stellar systems such as globular clusters and galactic nuclei. From a computational point of view the research group aims at the development of simulation environments for solving the equations for gravitational dynamics, stellar structure and evolution, hydrodynamics and radiative transfer. Calculations are performed on computers built by the research group and equipped with GRAPE hardware or graphical processing units (GPU) but also using supercomputers and grids. My most important activity over the last 5 years has been the initiation, development and building of the Astronomical Multi-purpose Software Environment (AMUSE). The source code of AMUSE is free to the community and can be downloaded from the project website {\tt http://amusecode.org}. At the moment AMUSE is producing new scientific results. Over the last few years my group has been producing over 20 scientific publications using the AMUSE framework on topics that range from planet formation, star cluster dynamics, gamma-ray bursts and supernova to cosmological structure formation simulations.

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.