The Distribution and Composition of Intergalactic Clouds at Large Red-Shifts [and Discussion]

Abstract

Most of the sharp absorption lines in the spectra of quasars of high red-shift are single Lyman-ɑ lines. The stronger ones have associated Lyman- β or Lyman-y lines but not lines of heavy elements. Recent statistical studies have shown that the density of Lyman-ɑ absorption lines is statistically the same in all quasars and that the lines are randomly distributed, with no tendency to cluster. It is now thought that the single Lyman-ɑ absorption lines are produced by primordial, intergalactic clouds. Studies now in progress are aimed at giving limits on the heavy-element composition of the clouds, as well as a value for the deuterium abundance of primordial gas.

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