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The First Stars and Galaxies: Challenges for the Next Decade Participants
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Talk
Title: The Pop III IMF: A Progress Report Author(s): Michael L. Norman Abstract: The standard view, based on detailed numerical simulations, is that Pop III stars are born massive >100 Ms. The physics behind this is simple and robust: the Jeans mass in primordial gas clouds is of this order because the properties of the primary coolant: molecular hydrogen. Recent ultra-high resolution simulations are beginning to show that some cores may fragment as they collapse to near stellar density, implying somewhat lower final masses. It has also been shown that DH cooling in preionized but still primordial gas may produce secondary Pop III stars in the range 30-50 Ms. On the other hand, energy release from dark matter annihilation may partially offset baryonic cooling processes at high densities and increase their final mass. The Pop III mass scale is thus a moving target at the present time, and it may be more productive to think in terms of a Pop III IMF and not a single characteristic mass. In this talk I review recent work in this area and suggest a strategy for future progress.
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