%0 Generic
%A Magg, Mattis
%C Heidelberg
%D 2022
%F heidok:31336
%R 10.11588/heidok.00031336
%T The Cosmological Transition to Metal-Enriched  Star-Formation
%U https://archiv.ub.uni-heidelberg.de/volltextserver/31336/
%X The first stars in the Universe mark the beginning of the epoch referred to as Cosmic Dawn.  Due to their metal-free nature, they are believed to be distinctively different from present-  day stars. While they are considered to be important in shaping the early Universe, little is  known about their properties. This thesis addresses several indirect methods of constraining  these properties, with a particular focus on the transition from metal-free to metal-enriched  star formation. To this end, I employ and develop a variety of analytical estimates, semi-  analytical models and a numerical simulation. By analysing the non-detection of metal-free  stars, I confirm that these stars must on average have been far more massive than present-  day stars. An analytical model and a careful review of numerical simulations demonstrate  that the interaction between the first supernovae and their ambient medium is key to un-  derstanding the most metal-poor stars known today. With a simulation of the massive  metal-free stars exploding as pair-instability supernovae, I highlight the tension implied by  the non-detection of their nucleosynthetic fingerprint. Finally, I use a semi-analytical model  to reveal the sensitivity of future 21 cm absorption detections to the time-delay between the  first supernovae and the second generation of stars. The results, tools, and methods of this  thesis will find application in future theoretical studies and in the analysis of upcoming  observations.