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Norman, M.L. Paschos, Paschalis 2015-09-25T22:35:37Z 2015-09-25T22:35:37Z 10000-01-01 2005 2005 In the second part of this work, we address topics on the metal enrichment of the IGM. An overview of the current research in the cosmic metal evolution is provided in Chapter (5). In Chapter (6), we investigate the pre-enrichment of the IGM by parametrizing the metal abundance as dependent on the local baryon mass. We show that the UVB is an important bias because it preferentially keeps carbon ionized at the CIV state in the Lyalpha forest mass range. In Chapter (7), we explore whether metal feedback from Population III stars (z ∼ 15) alone explains the metal abundance and distribution at later redshifts. This idea is expanded in Chapter (8), by including an additional feedback from Population It stars formed in dwarf galaxies at redshifts z ≲ 10. We conclude that, the PopIII metals alone are insufficient to explain the detected levels of metal enrichment in the observable Universe. We find that at late redshifts a significant portion of the primordial metal component was transported into the voids. Therefore, signatures in transmission spectra from such regions would sample the primordial metals. Made available in DSpace on 2015-09-25T22:35:37Z (GMT). No. of bitstreams: 2 license.txt: 4848 bytes, checksum: 96035ab3f5e1c23cc7138a224ce498bd (MD5) 3202151.pdf: 8519369 bytes, checksum: 10e9bca97b8e9465d483abdc0a50d193 (MD5) Previous issue date: 2005 Embargo set by: Seth Robbins for item 86463 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs U of I Only 264 p. Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2005. http://hdl.handle.net/2142/85182 (MiAaPQ)AAI3202151 eng Physics, Astronomy and Astrophysics On the Ionization and Chemical Evolution of the Intergalactic Medium text Astronomy Astronomy University of Illinois at Urbana-Champaign Dissertation Ph.D.