Resolving Stellar Populations in Ultra-Faint Dwarf Galaxies with HST

Ultra-faint dwarf galaxies are among the faintest and most dark matter-dominated systems known. This project uses archival Hubble Space Telescope photometry to analyse colour–magnitude diagrams, identify binary stars, characterise the stellar mass functions and metallicity distributions in these systems. The results will improve understanding of star formation in extreme environments and provide essential preparation for future surveys such as the Vera Rubin Observatory Legacy Survey of Space and Time (LSST).

school Student intake

This project is open for Honours and PhD students

Observatory

Mount Stromlo Observatory

label Research theme

Galactic archaeology

traffic Project status

Current

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About

Ultra-faint dwarf galaxies represent some of the most extreme stellar environments in the Universe. With very low luminosities, low metallicities, and high dark matter fractions, they provide unique laboratories for studying star formation and stellar evolution under primitive conditions. Their stellar populations preserve information about early star formation and the assembly of galaxies.

This project focuses on analysing deep archival imaging from the Hubble Space Telescope (HST) to construct precise colour–magnitude diagrams (CMD) of ultra-faint dwarf galaxies. The student will perform photometric reduction and calibration using standard techniques, ensuring high precision and completeness.

A major goal is to identify and characterise binary star populations. Binary systems affect CMD morphology and influence measurements of stellar mass functions. Using statistical modelling and Bayesian inference methods, the student will quantify the binary fraction and distribution of binary parameters.

The project will also measure the stellar mass function and metallicity distribution, providing insight into the star formation history of these systems. This work is particularly important in preparation for upcoming surveys such as LSST, which will discover many new ultra-faint dwarf galaxies but with different observational characteristics. The experience gained in analysing HST and possibly JWST data will help develop techniques applicable to future datasets.

Potential extensions include analysis of JWST data, providing deeper insight into the faint stellar populations.