Title Promoter Affiliations Abstract "Galaxies’ Anatomy - panchromatic SED modelling of spatially resolved galaxies in the local Universe" "Maarten Baes" "Department of Physics and astronomy" "Galaxies are an amalgamation of several components (dark matter, stars, gas, and dust), constantly interacting with one another. This interaction is imprinted on the spectral energy distribution (SED) of a given galaxy. Through a detailed study of the panchromatic SED we can shed light on the astrophysical processes that regulate galaxy evolution. However, the current SED modeling approaches come with many caveats and limitations. One of the main issues is that the star-formation histories (SFH) are usually poorly modeled, with significant systematics on parameters as the stellar mass or star-formation rate as a result. Moreover, global SED fits yield parameters that can deviate systematically from more reliable spatially resolved SED fits. We propose a full SED fitting of a representative sample of resolved galaxies, based on a combination of panchromatic imaging and spectroscopic data. We will adopt a fully Bayesian SED modeling framework and an innovative spatial image reconstruction technique to generate maps of the most important physical galaxy parameters. We will use these maps to quantify the bias between global and local estimates, to characterize dust scaling relations on both local and global scales, to investigate dust heating mechanisms in galaxies of different types, and to analyze the SFH on local scales. We will compare our results to those obtained using other methods. Our results can serve as interesting and original benchmark for galaxy evolution models." "Unveiling the hidden cold dust in nearby spiral galaxies" "Maarten Baes" "Department of Physics and astronomy, CEA Saclay" "Cosmic dust grains are tiny solid particles in the interstellar medium of galaxies. Characterising their physical properties is crucial to understand the evolution of galaxies. In the past decade, our knowledge on cosmic dust has increased substantially, thanks to observational data from UV to far-infrared wavelengths. However, one important part of the spectrum, the mm range, has largely remained terra incognita. Until now, the lack of high-quality mm observations, as well as limitations in modelling the interplay between dust and starlight, have prevented us from mapping all the dust in nearby galaxies and firmly characterising its physical properties. We want to exploit new observational data in the mm range and new advances in modelling techniques to accurately model, for the first time, the interplay between starlight and dust in a sizeable sample of nearby spiral galaxies. We will use our models (1) to search for cold dust, (2) to quantify the importance of different emission mechanisms in the mm range, (3) to look for evidence for a variation of the dust properties between and within galaxies, (4) to quantify the contribution of different dust heating mechanisms, and (5) to constrain the dust grain shape distribution in galaxies. We believe that this project can have a wide impact, from detailed studies of nearby galaxies to the understanding of galaxies at high redshift." "Dynamical structure and dark matter content of galaxies 7 billion years ago with the Large Early Galaxy Astrophysics Census survey." "Arjen van der Wel" "Department of Physics and astronomy" "I will use the ground-breaking spectroscopic LEGA-C survey to understand the star-forming phase of disk galaxies at a look back time of 7 billion years by studying the dynamics of ionised gas. The new data is of unprecedented high quality for its sample size of thousands of galaxies and contains for the first time detailed information about the dynamics, ages and chemical composition of the stellar content. I will constrain, for the first time, the radial profiles of gas velocity dispersion, which is of paramount importance to accurately measure their total masses and to test different hypotheses on the origin of disordered motions in distant galaxies. The radial profiles will set a new standard for future observations with the upcoming generation of telescopes and will provide improved constraints on scaling relations such as the Tully-Fisher relation of stellar mass and rotational velocity. The ultra-deep data can also be used to trace the faint outskirts of galaxies and to derive constraints on the amount and distribution of dark matter. My work will significantly improve our knowledge of the evolutionary history of galaxies in the universe today, including the Milky Way, and will serve as an explicit test of the current generation of high-resolution cosmological simulations." "The infrared emission of galaxies via machine learning techniques" "Maarten Baes" "Department of Physics and astronomy" "For a typical galaxy like the Milky Way, roughly one third of all starlight is re-processed through cosmic dust. The only way to directly observe and measure the interstellar dust content of galaxies uses observations at far-infrared and sub-millimeter (FIR/submm) wavelengths. Unfortunately, there are now no FIR/submm missions operational or approved. In principle, however, it should be possible to predict the FIR/submm emission from a galaxy, if we have UV, optical and nearinfrared imaging data at hand. We propose to develop a framework based on supervised machine learning techniques to predict the FIR/submm emission of galaxies from UV to NIR fluxes. We will train the algorithm with available state-of-the-art multi-wavelength data sets, both on global and on local (~100 pc) scales. We will use our framework to investigate the physical properties that drive the shape of the FIR/submm spectral energy distribution, and to investigate the influence of environment and morphology on the FIR/submm properties of galaxies. We will also construct a FIR/submm atlas of about 100 large nearby galaxies, at an angular resolution that cannot be obtained observationally, and use these images to test more complex radiative transfer modelling techniques." "The resolved lifecycle of metals and dust in nearby galaxies" "Ilse De Looze" "Department of Physics and astronomy" "Interstellar dust makes up only 1% of the interstellar mass, but dust grains play a vital role in the formation of molecular hydrogen and in the cooling of molecular clouds enabling these clouds to gravitationally collapse and form new stars. To model and infer the influence of dust on the efficiency of star formation, we need to understand how dust forms and evolves in galaxies. With this FWO project, we will develop resolved Dust and Element evolUtion modelS (DEUS) that will be used to interpret the resolved lifecycle of metals and dust in three Local Group galaxies. With these galaxies spanning a factor of 5 in metallicity range, we will probe different regimes in the dust lifecycle and diagnose the dominant sources of dust production at different metallicities. We will use the superb resolution and plethora of observational constraints to break existing model degeneracies and improve on poorly constrained model parameters resulting from global galaxy studies. My combined expertise in observational studies and modelling of dust in galaxies and supernovae will provide the necessary foundation for this pioneering study of the origin of interstellar dust in the Universe. To increase the visibility of the project, we will provide a complete dust formation and destruction model, and sets of numerical recipes applicable to a wide range of cosmological simulations, which will be indispensable to study the effect of dust on star formation and galaxy evolution." "Radiation-hydrodynamics simulations of dwarf galaxies with Shadowfax+CMacIonize" "Sven De Rijcke" "Department of Physics and astronomy" "Dwarf galaxies are ideal probes of the physical processes that drive galaxy evolution because their low masses make them extremely vulnerable to the effects of these processes. While this is obviously a good point, it also implies that numerical simulations of dwarf galaxies need to describe these physical processes as realistically as possible. For this FWO project, we plan to extend the capabilities of Shadowfax+CMacIonize, a novel radiation hydrodynamics simulation code and to use it for very realistic, high-resolution 3D simulations of dwarfs that, after having evolved in isolation for billions of years, are having their interstellar gas stripped away by ram pressure while falling supersonically into the Milky Way halo. We will make robust predictions for the observable properties of the Milky Way satellites and compare these with the observations as a crucial test of our understanding of (dwarf) galaxy evolution. Secondly, these simulations will serve to provide a robust estimate of the UV photon escape fraction (a crucial ingredient of computations of the cosmic UV background that reionized the early universe), its dependence on galaxy mass, time, starformation rate, ISM substructure, ... and its cosmic variance. Our results will advance the fields of galaxy evolution and cosmology. Since our radiation hydrodynamics code is publicly available, the project will also benefit other research communities." "An investigation of the dust energy balance in HEROES/NHEMESES galaxies" "Maarten Baes" "Department of Physics and astronomy" "We will perform, for the first time, a uniform and unbiased radiative transfer modelling of a sample of 19 large edge-on spiral galaxies, based on observational data covering UV to submm wavelengths. Based on this unprecedented set of 3D models, we will investigate the detailed distribution of dust in spiral galaxies, quantify the importance of the dust energy balance problem, and investigate various possible causes." "The relation between gas, dust and total mass in galaxies across the Hubble sequence" "Maarten Baes" "Department of Physics and astronomy" "For 32 galaxies across the Hubble sequence the gas-to-dust ratio will be studied in unprecedented detail. Also, for the very first time the relation between interstellar dust and total mass will be investigated for different phases of galaxy evolution. Finally, a new method to trace the density of the interstellar medium will be thoroughly tested." "Panchromatic modeling of stars and dust in face-on spiral galaxies" "Maarten Baes" "Department of Physics and astronomy" "Benefetting from the recent improvement in resolution and wavelength coverage of infrared/submillimeter observations, we can construct panchromatic radiative transfer models of the stars and dust in galaxies. The construction of self-consistent, high-resolution 3D radiative transfer models of face-on spiral galaxies allows us to study the distribution, grain composition and emissivity of dust. We can furthermore investigate the main heating mechanisms on local and global scales within galaxies and infer how the heating by young stars can be probed most reliable." "Dark matter in dwarf galaxies" "Sven De Rijcke" "Department of Physics and astronomy" "Dwarf galaxies hold the key to solve some of the most important questions in current extragalactic astronomy regarding galaxy environment, star formation and dark matter. Through stellar population analysis, dynamical modelling and numerical simulations we will examine the controlling mechanism of star formation, the role of the dark matter, the dwarf dark-matter halo occupancy and the physical processes behind the observed scaling relations."