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The First Stars and Galaxies: Challenges for the Next Decade Participants
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Talk
Title: Very Blue UV-Continuum Slopes of Star-Forming Galaxies at z ~ 7-8 and the Evolution to z ~ 2-4 Author(s): Rychard Bouwens Abstract: The new WFC3/IR instrument on HST enables us to survey the sky in the near-IR 40x more efficiently than ever before -- permitting us to make enormous strides in our searches for z>=7 galaxies. Already deep, wide-area observations exist over some ~52 arcmin**2 in the HUDF09 + ERS fields. With these data, we have been able to select some 40+ z~7 galaxy candidates, 20+ z~8 galaxy candidates, and even some possible z~9 galaxies over a 3 magnitude range in luminosity -- adding significantly to the ~20-30 z~7 candidates known prior to WFC3/IR. In this presentation, I will present the UV-continuum slopes measured for star-forming galaxies at these times and the great contrast with that found for similar luminosity star-forming galaxies at later times, i.e., z~2-4. I will then discuss the likely implications of these very blue UV-continuum slopes for the dust content, metallicities, or escape fractions of low-mass star-forming galaxies at very times.
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