AAS 205th Meeting, 9-13 January 2005
Session 69 Cosmology: Population III, Distant SNe, and Dark Energy
Poster, Tuesday, January 11, 2005, 9:20am-6:30pm, Exhibit Hall

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[69.01] What Will It Take to Find the First Stars?

J. Tumlinson (University of Chicago)

Recent discoveries of galaxies at z = 5 - 6.5 place the truly first, metal-free stars just over the horizon. The very blue colors and strong Ly\alpha in these early galaxies presage the large changes in observational signatures expected for the earliest phases of galactic chemical enrichment. I review the unique properties of metal-free stars that have important observational signatures. Most features unique to low-metallicity stars derive from their high temperatures and hard spectra, so that nebular emission lines are likely to be the most efficient means of detecting low- or zero-metallicity star formation at high redshift. Recent projections of the detectability of these signatures have optimistically pointed out that detection of these objects is feasible with the James Webb Space Telescope and 30-m class ground-based telescopes. If metal-free populations contribute significantly to reionization and dominate the enrichment of extremely metal-poor Galactic halo stars, then a primordial IMF with M = 10 - 100 M\odot is preferred over Very Massive Stars (VMSs). I explore methods for testing IMF and early enrichment with optical and NIR emission, high-z SN and GRB rates, and low-metallicity Galactic stars. Particular attention is paid to substantial degeneracies in the available diagnostics for individual galaxies at high redshift. I argue that only the combination of all the available observational constraints will fully illuminate the mysteries of the true first stars.

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© 2004. The American Astronomical Society.