The Pregalactic Universe

The Pregalactic Universe - The Pregalactic Universe There...

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The Pregalactic Universe There are several recognized processes from the early universe that leave relic effects setting the stage for galaxy formation and evolution. We deal here with the first generarion of stars, primordial nucleosynthesis, the epoch of recombination, and the thermal history of various cosmic backgrounds. The First Stars Several kinds of evidence point to an early (pregalactic) source for a small level of enrichment in heavy elements (especially, at this point, oxygen). These include the patterns of abundances in extreme Population II stars in the Milky Way and the O/H ratio in intergalactic gas. This early enrichment may be the first evidence of the first generation of stars, variously known as Population III, very massive stars (VMOs), or very massive objects (VMSs). They must have been able to form in a way different from what we see in today's Universe, without any dust or heavy elements to assist in cooling the gas during collapse. This would tip the typical masses to
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This note was uploaded on 11/10/2011 for the course AST AST1002 taught by Professor Emilyhoward during the Fall '10 term at Broward College.

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The Pregalactic Universe - The Pregalactic Universe There...

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