One of the most important puzzles in modern astrophysics is the nature of dark matter. Stellar streams, formed by tidal stripping of the stars from globular clusters or dwarf galaxies, behave as a... Show moreOne of the most important puzzles in modern astrophysics is the nature of dark matter. Stellar streams, formed by tidal stripping of the stars from globular clusters or dwarf galaxies, behave as a group of test particles allowing us to measure the Milky Way’s dark matter content and, therefore, offering us a key to understanding its nature. Open clusters, loosely bound groups of stars that move through the Galaxy together, are, in contrast, an important driver of stellar evolution research. This Thesis presents our studies of these Galactic substructures and the conclusions we can draw on the larger Universe and physics based on these local observations. In chapters 2 - 4, we apply a novel method to map the Milky Way’s dark matter content using stellar streams, taking care to understand the various possible contributors to the systematics. Chapter 5 is dedicated to the study of the Hyades open cluster. Show less
The aim of this work is to study starbursts and the dynamical processes involved, both from gas and stellar components. For this purpose, one nearby galaxy with a nuclear starburst was selected, as... Show moreThe aim of this work is to study starbursts and the dynamical processes involved, both from gas and stellar components. For this purpose, one nearby galaxy with a nuclear starburst was selected, as well as a sample of 6 ultraluminous infrared galaxies (ULIRGs). Observations of these sources were carried out with SINFONI, the spectrograph for integral field observations in the near-infrared, an instrument that is mounted on the VLT in Chile. The thesis contains a study of the spectral features that are characteristic for starbursts, and a comparison of dynamical masses and mass-to-light ratios of the ULIRGs, calculated with different methods both from stellar dynamics and gas dynamics. Show less
In this thesis we explore new techniques to study the dark and luminous matter in the outskirts of galaxies. To determine the mass and shape of the dark matter halo around the early-type galaxy NGC... Show moreIn this thesis we explore new techniques to study the dark and luminous matter in the outskirts of galaxies. To determine the mass and shape of the dark matter halo around the early-type galaxy NGC 2974, we measure the kinematics of its large neutral gas ring. We combine these large-scale kinematics with the central kinematics of the ionised gas to construct mass models of this galaxy. For galaxies that do not contain neutral gas, we use integral-field spectroscopy to measure the stellar kinematics at large radii. Briefly, we use the spectrograph as a "photon-collector", to obtain spectra with sufficient signal-to-noise. The kinematics are used to model the dark haloes around the galaxies NGC 2549, NGC 3379 and NGC 821. We also measure the line strengths from the spectra to determine the properties of the stellar population in the outer parts of these systems. Finally, we take a look in the high-redshift Universe, by studying the Lyman Alpha emission of a system at redshift 3.1 (LAB1). We obtain integral-field spectra to study the distribution of the ionised gas, as well as the emission profile, and discuss possible formation and ionisation scenarios. Show less
