April 8
Inner Structure and ISM of Early Galaxies from Cosmic Dawn to the EoR: Insights from FirstLight Simulations and JWST/ALMA
Speaker: Dr. Yurina Nakazato, CCA, Flatiron Institute
Abstract: The unprecedented sensitivity and resolution of JWST and ALMA have transformed our view of the early Universe. At z > 6, we observe diverse galaxy morphologies including clumpy and disk-like systems, spatially inhomogeneous ISM, and most strikingly, an overabundance of UV-bright galaxies extending to z > 10. In this talk, I present theoretical insights into these observations using the FirstLight cosmological zoom-in simulations.
I will first discuss the inner structure of EoR galaxies, focusing on the origin of clumpy morphologies associated with bright [OIII] emission. By combining stellar particle-based HII region modeling with the radiative transfer code CLOUDY, we show that [OIII]-bright clumpy structures are predominantly formed through major mergers. I will also present spatially resolved dust attenuation curves in EoR galaxies, finding that attenuation in clumps differs systematically from diffuse regions and from system-integrated values.
I will then turn to the overabundance of UV-bright galaxies at z > 10, which we address through both high star formation efficiencies in FirstLight and an analytical dusty outflow scenario. Finally, I will introduce ongoing JWST and ALMA observational collaborations that support these theoretical predictions and outline future multi-wavelength studies.
Host: Ankita Bera