Master's Thesis Defense by Mikkel Larsen

Title: Comparative Analysis of High-Mass Star-Forming Regions

Abstract:  Studying the formation of high-mass stars is a challenge, and much is still unknown about the formation process. The difficulties arise primarily due to the high-density environments in which they are born, blocking everything but the longest wavelengths. Understanding the process is important as these stars significantly impact their surroundings, including the creation of many heavy elements, energizing the ISM and the supernovas responsible for kickstarting some of the low-mass star formation. The Atacama Large Millimeter/submillimeter Array (ALMA) has surveyed fifteen high-mass star-forming regions to allow for a comparative analysis of the environments needed to form high-mass stars. The conditions within these HMSFRs have been compared using the molecules H13CN and H13CO+ as tracers. The mean velocities, as well as velocity distributions, have been calculated using three methods, revealing similarly structureless turbulent motion in most of them. The column densities of the two molecules revealed that most of the HMSFRs contain isolated dense cores, in which the relative densities do not match those found in low-mass regions.

Supervisor: Jes Kristian Jørgsensen

Censor: Hans Kjeldsen, Aarhus Universitet