Understanding how galaxies form, interact, and evolve comes largely from comparing theory predictions with observational data. Numerical simulations of galaxies provide the most accurate approach... Show moreUnderstanding how galaxies form, interact, and evolve comes largely from comparing theory predictions with observational data. Numerical simulations of galaxies provide the most accurate approach to testing the theory, as they follow the non-linear evolution of gas and dark matter in great detail and incorporate numerous baryonic processes, among which are energy feedback from supernovae (SNe) and Active Galactic Nuclei (AGN). In this thesis, we show the results of the development of the new model COLIBRE for cosmological simulations of galaxy formation that include a cold interstellar medium. First, we present a new SN feedback recipe developed for COLIBRE, whereby SN energy is injected into the gas in thermal and kinetic forms, and the total energy and momentum of the system of gas and stars are exactly conserved. Second, we conduct a detailed comparison of different ways in which SN energy is distributed in the gas environment around young stellar populations. Third, by using our simulation setup originally developed to test COLIBRE’s SN feedback, we show that the radioactive isotope Fe60 that has been detected on Earth is likely of SN origin. Finally, we present the calibration of the SN and AGN feedback of the COLIBRE model using machine learning. Show less
This thesis focuses on the study of transient and variable radio sources in the universe. Transient signals, unlike a source constantly visible, change in their brightness (or flux) over a certain... Show moreThis thesis focuses on the study of transient and variable radio sources in the universe. Transient signals, unlike a source constantly visible, change in their brightness (or flux) over a certain length of time. While there are a plethora of transients over short intervals in radio astronomy that last less than a minute, this thesis will primarily cover those which play out over many years and decades. Show less
Using n-body and stellar evolution simulations I model different star systems. Through the use of a large number of n-body simulations I model the effect of subvirial initial conditions on the... Show moreUsing n-body and stellar evolution simulations I model different star systems. Through the use of a large number of n-body simulations I model the effect of subvirial initial conditions on the evolution of star clusters and shed light on a dynamical mechanism for rapid mass segregation in young clusters. Using stellar evolution simulations I estimate there to be 10^8 intermediate mass black holes in the local universe. Lastly, I explore the effect of a supernova in a triple star system Show less
