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The quest of measuring star-formation histories to elucidate the first galaxies

The last great unknown of the cosmic history is when, why and how the first galaxies formed after the Big Bang. These galaxies played an important role in re-ionizing the universe and are also an important tracer of early structure formation. I will present new results on the stellar populations of the most distant galaxies currently known. By combining Hubble Space Telescope observations with Spitzer imaging data, I will show how challenging it is to measure basic physical properties of these objects such as star-formation rates, stellar masses and stellar ages. In particular, the current measurements greatly depend on the assumptions (priors) for the spectral energy distribution modeling. Finally, I will discuss how the James Webb Space Telescope (JWST) will revolutionize this field next year and allow us to probe and characterize the first generation of galaxies in much greater detail. In particular, I will present an overview of the JWST Advanced Deep Extragalactic Survey (JADES), a joint program of the JWST/NIRCam and NIRSpec Guaranteed Time Observations (GTO) teams involving 950 hours of observation.

Archived Recording:


Sandro Tacchella, Ulsan National Institute of Science and Technology

September 15, 2021
11:00 am - 12:00 pm