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Zooming into primordial galaxies and star-forming complexes with JWST.
Rosati P.
The unprecedented combination of angular resolution, sensitivity and near- and mid-infrared coverage offered by the James Webb Space Telescope is transforming our view on how galaxies form and evolve from their earliest stages. I will report on some highlights in the search and physical characterisation of the most distant galaxies and star-forming complexes, particularly taking advantage of JWST observations of strongly lensing galaxy clusters. Gravitational lensing amplification and magnification allows us to extend to low luminosities and stellar masses (below $10^6 M_\odot$) our knowledge of star-forming systems in the first billion year of cosmic history, resolving their inner structure down to parsec resolution. These studies complement those in the field which have found a surprisingly large number of luminous galaxies at $z> 9$, challenging theoretical expectations. JWST spectroscopic observations of low-luminosity systems are critical to identify the first generation of extremely metal poor stars and ultimately the sources of reionization in the Universe.