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JWST’s first glimpse of the first galaxies

Event Image
Thursday, May 04, 2023
2:00 pm - 3:00 pm
James Trussler
Duke Cosmology Seminar Series

Speaker: James Trussler (The University of Manchester)

Title: JWST's first glimpse of the first galaxies

JWST has ushered in a great new golden age of astronomy, opening the possibility of discovering and characterising primordial galaxies deep within the epoch of reionisation (EoR). In this talk I will therefore highlight how JWST has already begun to transform our understanding of the formation and evolution of the first galaxies in the Universe. First, I will discuss the first images and spectra taken by JWST - centred on the now-famous galaxy cluster SMACS 0723 - which immediately demonstrated that intense star formation and extreme nebular conditions are likely the norm, rather than the exception, for galaxies in the EoR. Second, I will discuss our search for EoR galaxies exhibiting two strong spectral breaks in their photometry, providing evidence for evolved stellar populations in these galaxies, and thus enabling us to indirectly infer the epoch when the first galaxies began to form. Third I will introduce a set of photometric and spectroscopic diagnostics that I have developed to identify potential first galaxy candidates, i.e. chemically pristine Population III galaxies in the EoR. Finally, I will close by revealing whether any convincing Pop III candidates have been identified from the early Webb data.

Contact: Chien-Hao Lin