JWST’s view on Star Formation and mass growth in Early Galaxies

Date:

I was invited to visit the department and give a special seminar at the Kavli Institute for Cosmology at the University of Cambridge. The abstract is attached below.

JWST’s view on Star Formation and Mass Growth in early Galaxies

JWST’s NIRCam has transformed our understanding of galaxy structure in the early Universe through unprecedented spatial resolution and sensitivity. Deep wide and medium-band photometry enables precise rest-UV and optical SED constraints, revealing both opportunities and challenges for stellar population modeling.

I will present recent work on the galaxy stellar mass function and total stellar mass density evolution at z > 7, followed by spatially-resolved analysis of 200+ galaxies at z > 5. This reveals how internal structure affects integrated stellar mass estimates through ‘outshining’ effects. I will examine systematic uncertainties in high-redshift SED fitting—including IMF, SPS models, SFH parametrizations, and dust laws—and their impact on derived parameters.

Finally, I will discuss moving beyond traditional SED fitting using machine learning approaches, particularly simulation-based inference (SBI), for large-scale Bayesian inference from wide-area surveys. I will present ongoing work making SBI more accessible for fitting photometry and spectroscopy, enabling rapid constraints on stellar, nebular, and AGN properties in high-redshift galaxies.