Le 14 septembre 2018
De 10h30 à 12h00
David Elbaz
CEA
Our understanding of galaxy formation is largely based on the use of the Lyman discontinuity in the ultraviolet spectrum of galaxies. Discovering « Lyman break galaxies » revolutionized our vision of the distant Universe, providing a « complete » picture of the cosmic history of star formation and offering the best candidates for reionizing the Universe.
However, there are signs that pieces of the puzzle may be missing. The progenitors of massive ellipticals with compact stellar cores found at z~2 remain elusive; quasars and other distant monsters seem to hide most of their activity by dust attenuation; the density of cosmic star formation deduced from distant gamma-ray bursts suggests that much of the history of galaxy growth is still elusive.
Is a major episode of our series on the history of the universe missing?
I will present results (published and unpublished) obtained largely with the Atacama Large Millimeter Array, ALMA, that change our understanding of the history of galaxy formation and evolution, including the discovery of HST-dark galaxies, invisible to even the deepest images of the Hubble Space Telescope. Using ALMA to dissect galaxies, I will show a clear dichotomy between transparent UV regions and opaque regions in distant galaxies. Finally, I will use distant dusty galaxies as probes to search for distant galaxy clusters in formation.