Dwarf galaxies in our Universe are sensitive to small-scale evolutionary processes, thus of-

fering unparalleled opportunities for testing galaxy formation theories and understanding

dark matter behaviour. Their proximity to the Milky Way allows for detailed structural

and compositional analysis, which is crucial for refining cosmological models.

The ‘Engineering Dwarfs at Galaxy Formation’s Edge’ (EDGE) project includes cos-

mological simulations that explore the low-mass dwarf regime in a Λ-Cold Dark Matter

(ΛCDM) cosmology with high mass and spatial resolution. These simulations are vital

for understanding dwarfs in a controlled environment, helping to differentiate the effects

of various physical processes. They offer systematic insights into feedback, accretion his-

tories, and environmental effects; factors often challenging to discern from observations

alone.

This thesis first examines the projected stellar ellipticities and the outer faint stellar

regions of isolated dwarf galaxies using the EDGE simulation suite. The simulations

show a broad range of projected ellipticities (0.03 < ε < 0.85) among dwarf galaxies,

mimicking tidal tails but owing to late-time accretion events of lower-mass companions.

The ellipticities in EDGE dwarfs match well with 19 Local Group (LG) and 11 isolated

dwarf galaxies, suggesting some LG dwarf ellipticities may arise from non-tidal scenarios.

A further inspection focuses on the stellar haloes of the dwarf galaxies within the

EDGE suite, analysing their accretion histories and stellar distributions. Findings indicate

that metal-poor stellar haloes form from minor mergers on smaller scales and both minor

and major mergers on larger scales. The simulations consistently show metal-poor stellar

haloes ([Fe/H] ≲ -3), aligning with observations and implying a common feature to be

expected in dwarf galaxies. Metallicity gradients within these haloes are highlighted, with

less massive systems exhibiting stronger gradients due to more homogeneous metallicity

distributions in their haloes.

Additionally, the discovery of ultra metal-poor stars ([Fe/H] < -4) near the centres

of EDGE galaxies is akin to findings in the Sculptor dwarf galaxy. This suggests dwarf

galaxies are prime targets for studying imprints of the first stars. By quantifying the

likelihood of detecting metal-poor stars within 1 kpc of the EDGE galactic centres, this

work reveals that dwarf galaxies with large half-light radii and low global metallicities

are promising sites for future spectroscopic surveys aimed at uncovering ancient stellar

populations.

Overall, the results presented here highlight the importance of dwarf galaxies in testing

dark matter models and understanding galaxy formation on small scales. Future observa-

tional campaigns will be crucial in validating these simulation results and expanding our

knowledge of the early Universe.