Galaxy evolution with JWST and HST

The formation and evolution of galaxies in the early universe is one of the open frontiers in observational astronomy.

Detailed studies of galaxies at extreme distances (high redshift, z), and of more nearby galaxies with similar properties, are needed to test current theories of how the galaxy populations we see today formed their stars.

Observational diagnostics of star forming galaxies – such as the luminosity and colors of their stellar populations, and spectroscopy of emission lines from the ionized gas clouds surrounding newly formed stars – are vital tools to progress our understanding.

The current and future space-based observatories (Hubble Space Telescope and James Web Space Telescope) provide data of spatial resolution and in wavelength ranges that are impossible to achieve with ground-based facilities.In this proposal we ask for funding to use data from the most competitive space observatories to address the following outstanding questions in extragalactic astrophysics:What is the structure and kinematics of ionized gas in star forming galaxies at very high redshifts, in the epoch when the universe was not yet fully re-ionized?What is the nature of stellar populations inside high redshift galaxies in terms of their mass and age?What are the properties of stars and ionized gas in galaxies producing giant Lya halos?What does observations of ionized gas kinematics and resolved stellar populations in nearby star burst galaxies tell us about galaxy formation?What are the physical conditions of very compact, intermediate redshift, emission line galaxies that leak ionizing photons into intergalactic space?What is the star formation history of IZw18, one of the chemically least evolved galaxies in the nearby universe?JWST will offer unprecedented spatial resolution and sensitivity over the 1-28 μm range, compared to any existing and near-future facility.

This makes JWST the ideal machine to study starburst galaxies in the early universe as well as nearby galaxies at infrared wavelength in great detail.