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Session 62 - Workshop on the Future of Antarctic Astrophysics - II.
Topical, Oral session, Wednesday, June 10
We will discuss various observable signatures of the first generation of stars and low-luminosity quasars, including the metal enrichment, radiation background, and dust opacity and emission they produce. To estimate the history of formation of dark-matter halos, we use an extension of the Press-Schechter formalism, incorporating the effects of pressure and molecular hydrogen dissociation. We then use the observed C/H ratio at z=3 in the Lyman-alpha forest clouds, to obtain an average the star formation efficiency in these halos. Similarly, we adjust the efficiency of black-hole formation, and the shape of quasar light curves to match the quasar luminosity function between redshifts z=2-4, to obtain the luminosity function of faint quasars at high redshifts.
We find that in a Cold Dark Matter models, either stars or quasars are expected to reionize the intergalactic medium at redshifts z=10-20. The corresponding damping of CMB anisotropies on small angular scales is 10-20%, detectable by future satellites such as MAP and the Planck Surveyor. We also find that the Next Generation Space Telescope will be able to directly image about 1-100 star clusters per square arcmin from redshifts above z=10, and a comparable number of faint quasars. However, we show that the lack of faint point sources in the Hubble Deep Field places a mild constraint on the models. The amount of dust produced by the first supernovae have an optical depth of 0.1-1 towards high redshift sources, and the reprocessed UV flux of stars and quasars distorts the CMB by a y-paramater comparable to the COBE limit, y=1.5e-5.
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