Preview

PDF, English (Yildirim PhD) - main document Download (11MB) | Terms of use

Abstract

In this thesis, a sample of nearby, compact, elliptical galaxies with high central stellar velocity dispersions are studied. By means of high quality photometric and spectroscopic observations, we analyse their structural properties and construct state-of-the-art orbit-based dynamical models to constrain their total mass budgets, including the contribution of stars, dark matter and a supermassive black hole. We demonstrate that our sample of compact ellipticals are outliers of the local population of elliptical galaxies, but their properties are consistent with massive and non-star forming galaxies at much earlier times (z=2). We postulate that our sample has passively evolved since z=2, which allows us to investigate these relic galaxies in unprecedented detail. All our objects are disky fast-rotators, devoid of a prominent pressure supported bulge, with a dominant stellar mass component inside one effective radius. We were able to detect an over-massive supermassive black hole in one galaxy and suspect that more will be detected in our sample. This strongly indicates that the growth of a supermassive black hole is not necessarily linked to the growth of a bulge. Finally, we show that at least three out of seven galaxies in our sample are embedded in a dark halo, with unambiguous evidence for a very massive dark halo in one particular object. The dark halo in this object, NGC 1281, consitutes 90 per cent of the total mass content within 5 effective radii, and the dark matter distribution cannot be reconciled with that predicted by cold dark matter simulations.