Understanding diversity: chemical and kinematic tracers of galaxy evolution

Project opportunity

This Earmarked Scholarship project is aligned with a recently awarded Category 1 research grant. It offers you the opportunity to work with leading researchers and contribute to large projects of national significance.

Understanding galaxy formation and evolution is a fundamental unresolved goal of Astrophysics today. Three of the six major questions outlined in the Decadal Plan for Australian Astronomy 2016–2025 advance the field of galaxy evolution: ‘How do galaxies form?’, ‘What is the nature of dark matter?’, ‘How are elements recycled through galaxies?’ These questions can be summed up in the specific motivation for this project, ‘How do the clumpy, irregular galaxies at the peak of cosmic star formation (cosmic high noon) become the familiar Hubble types we see today?’

The aim of these projects is to understand the fundamental physics behind the morphological evolution of galaxies. We are investigating the angular momentum and chemical abundance across the face of galaxies throughout the Universe, to construct a framework of chemokinematic diagnostics that can trace the evolution of galaxies of all kinds. 

There are two PhD projects on offer:

Project 1 is on galaxy angular momentum. A galaxy's morphology is quantified by the ratio of light in its central bulge compared with total luminosity. This 'bulge-to-total ratio' works reasonably well for nearby, well-resolved and regular galaxies, but not as well for distant galaxies which are more difficult to observe and are more often clumpy and irregular. The distribution of angular momentum within a galaxy fundamentally encodes information about that galaxy's evolution and morphology and consequently is a new physically-grounded method for classifying galaxies. This project involves developing this classification method for galaxies of all morphological types and at all redshifts.

Project 2 is on chemical abundance diagnostics. Chemical content is an important signature of a galaxy's lifecycle, as the buildup of elements from hydrogen and helium to heavier 'metals' is intimately linked to its history of star formation. There are two equally-justifiable methods for measuring chemical content based on regions of active star formation within galaxies, but the methods are not properly calibrated, so they do not agree. Moreover, they are valid in different regimes, so that we cannot accurately compare distant galaxies with those nearby, or massive galaxies with small ones. This project involves working with 3D spectroscopic data to obtain a complete three-dimensional picture of star-forming regions, and recalibrate the chemical content measurements.

Scholarship value

As a scholarship recipient, you'll receive: 

  • living stipend of $28,854 per annum tax free (2022 rate), indexed annually
  • tuition fees covered
  • single Overseas Student Health Cover (OSHC)

Supervisor

Dr Sarah Sweet

School of Mathematics & Physics

Email: s.sweet@uq.edu.au

Preferred educational background

Your application will be assessed on a competitive basis.

We take into account your

  • previous academic record
  • publication record
  • honours and awards
  • employment history.

A working knowledge of programming languages such as Python and/or R would be of benefit to someone working on this project.

The applicant will demonstrate academic achievement in the field(s) of astrophysics and the potential for scholastic success.

Latest commencement date

If you are the successful candidate, you must commence by Research Quarter 1, 2023. You should apply at least 3 months prior to the research quarter commencement date.

If you are an international applicant, you may need to apply much earlier for visa requirements.

How to apply

You apply for this project as part of your PhD program application.

View application process