On the Formation, Evolution, and Observation of Dark Compact Objects

Abstract

In this thesis, we present new ways that dark matter can form into compact, self-gravitating astrophysical objects, and their observable prospects. The distribution of these astrophysical compact objects and their properties can be used to constrain and differentiate between dark sectors. On the formation and evolution of these objects, we show how a dissipative dark sector can result in the formation of compact objects by considering two distinctly different formation mechanisms -- each with their own set of unique features. First, we investigate the formation of such compact objects from a subdominant inelastic dark matter model, which result in dark compact objects with masses comparable to stars and planets, and study the distributions of these objects. We find that the microphysics of the particle model is embedded in the properties of the astrophysical objects they make up. Second, we then demonstrate a novel mechanism for producing dark compact objects and black holes through a dark sector, where all the dark matter can be dissipative. Heavy dark sector particles can come to dominate the Universe and yield an early matter-dominated era before Big Bang Nucleosynthesis (BBN). Although the growth and collapse of perturbations are seeded in the early Universe, our cosmology can result in the late-time formation of fragmented dark compact objects and sub-solar-mass primordial black holes. On the observation of these objects, we demonstrate a new technique to search for dark compact objects. When dark matter comprising a dark compact object interacts with photons, the compact object can disperse light traveling though it. As these objects pass between Earth and a distant star, they act as ``lampshades'' that dim the star. We examine how dimming effects from clumps of dark matter in the Galaxy could be searched for in microlensing surveys, which measure the brightness of stars as a function of time. Using the EROS-2 and OGLE surveys, we show that a dimming analysis of existing data can be used to constrain dark sectors and could be used to discover dark matter in compact objects.