Spatially resolved star formation and quenching: insights from observations and simulations
type: CreativeWork
description: The cosmic star formation rate density is known to have declined by a factor of ~10 to present day after reaching its peak at z ~ 2. There were drastic differences in the star-forming conditions between z ~ 0 and z ~ 2, such that galaxies in the past were more star-forming and gas-rich. Given the complexity of the star formation histories of galaxies, it is not trivial to pinpoint the exact physical mechanisms responsible for the decline from z ~ 2 to z ~ 0. To do so, it is crucial to study the spatially resolved star formation activity of galaxies across a broad range of star-forming states - from those above to below the star-forming main sequence (SFMS). In this thesis, I use the Middle Ages Galaxy Properties with Integral Field Spectroscopy (MAGPI) survey to investigate how galaxies have fuelled, regulated and quenched their star formation activity at intermediate redshifts (z ~ 0.3). In the first science chapter, I map radial trends in star formation for both the star-forming and passive populations in the MAGPI sample at z ~ 0.3, using a combination of the Halpha emission line and the 4000 Angstrom break as star formation rate indicators. I then compare these trends to those measured in the local Universe (z ~ 0) and at cosmic noon (z ~ 1 - 2), to capture how star formation has progressed within galaxies across ~10 Gyrs of lookback time. I capture evidence for potential evolution in radial trends for galaxies above the star-forming main sequence (SFMS), from uniformly (z ~ 1) to centrally (z ~ 0) enhanced star formation. Galaxies below the SFMS tend to quench inside-out at all redshift epochs probed. In the second chapter, I use mock observations of galaxies from the EAGLE, Magneticum, and IllustrisTNG simulations to match MAGPI observational details including the average point spread function and pixel scale. Overall, there is no agreement in radial trends between MAGPI observations and the simulations, except for galaxies below the SFMS. All three simulation…
abstract: The cosmic star formation rate density is known to have declined by a factor of ~10 to present day after reaching its peak at z ~ 2. There were drastic differences in the star-forming conditions between z ~ 0 and z ~ 2, such that galaxies in the past were more star-forming and gas-rich. Given the complexity of the star formation histories of galaxies, it is not trivial to pinpoint the exact physical mechanisms responsible for the decline from z ~ 2 to z ~ 0. To do so, it is crucial to study the spatially resolved star formation activity of galaxies across a broad range of star-forming states - from those above to below the star-forming main sequence (SFMS). In this thesis, I use the Middle Ages Galaxy Properties with Integral Field Spectroscopy (MAGPI) survey to investigate how galaxies have fuelled, regulated and quenched their star formation activity at intermediate redshifts (z ~ 0.3). In the first science chapter, I map radial trends in star formation for both the star-forming and passive populations in the MAGPI sample at z ~ 0.3, using a combination of the Halpha emission line and the 4000 Angstrom break as star formation rate indicators. I then compare these trends to those measured in the local Universe (z ~ 0) and at cosmic noon (z ~ 1 - 2), to capture how star formation has progressed within galaxies across ~10 Gyrs of lookback time. I capture evidence for potential evolution in radial trends for galaxies above the star-forming main sequence (SFMS), from uniformly (z ~ 1) to centrally (z ~ 0) enhanced star formation. Galaxies below the SFMS tend to quench inside-out at all redshift epochs probed. In the second chapter, I use mock observations of galaxies from the EAGLE, Magneticum, and IllustrisTNG simulations to match MAGPI observational details including the average point spread function and pixel scale. Overall, there is no agreement in radial trends between MAGPI observations and the simulations, except for galaxies below the SFMS. All three simulation…
author: Mun, Marcie
language: en_AU
date published: 2025
date modified: 2026-07-24T00:54:57Z
provider: Australian National University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Australian National University

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property ID: Handle
value: https://hdl.handle.net/1885/733772734