Colóquios do NAT

17/06 - JWST’s view on star formation and mass growth in early galaxies

M.Sc. Thomas Harvey (Jodrell Bank Centre for Astrophysics) 

The unprecedented spatial resolution and sensitivity of JWST's NIRCam instrument has revolutionized our ability to probe the internal structure of galaxies in the early Universe. Wide and medium band photometry from deep NIRCam observations has enabled precise constraints on the rest-UV and optical spectral energy distribution (SED) of high-redshift galaxies, which is essential for reliability modelling their stellar populations using SED fitting. Modelling these high-quality observations has presented new challenges and uncovered some limitations with existing SED fitting tools and assumptions. In this talk I will review some of the recent and exciting developments in the study of high-z galaxies with JWST, and provide a brief overview of the relevant background and methodology used. Key results I will highlight include new estimates of the galaxy stellar mass function and evolution of the total stellar mass density at z>7. I will also discuss our spatially-resolved analysis of over 200 galaxies at z > 5, where we explore the internal structure of high-redshift galaxies and quantify the impact of ‘outshining’ on integrated stellar mass estimates. I will address the challenges when modelling galaxy SEDs at high-redshift and explore the systematic effects of SED fitting assumptions such as Initial Mass Function, stellar population synthesis (SPS) model, star formation history parametrization or dust law, on the derived parameters. I will finish by discussing recent work to move beyond traditional SED fitting techniques to allow large-scale inference of galaxy properties for wide-area space and ground-based surveys.