Event

Galaxies have grown significantly in size since the early Universe. While quiescent galaxies grow primarily through galaxy mergers, star-forming galaxies grow by accreting gas from their surroundings and forming new stars. Observations of star-forming galaxies over the last ~10 billion years reveal that they are larger in the rest-frame UV than in the rest-frame optical, which has been interpreted as evidence of inside-out growth (i.e., galaxies grow their central regions first and their outskirts later on). In this talk, I will present recent results that provide an in-depth view of how galaxies, and their individual components, have grown in size. In addition, by comparing multi-wavelength Hubble Space Telescope observations to simulations where we can control for the effects of dust, I will also show that size variation as a function of wavelength, previously believed to be caused by inside-out growth, can instead be explained by dust attenuation alone. I will discuss the implications of these results and will conclude with remarks on investigating the effects of dust on galaxy sizes further with the James Webb Space Telescope and additional cosmological simulations that use different dust prescriptions.