{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/85182"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/85182","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"On the Ionization and Chemical Evolution of the Intergalactic Medium","abstract":"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.","abstract_html":"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.","abstract_has_math":false,"creators":["Paschos, Paschalis"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Astronomy","degree_department":null,"school":null,"contributors":["Norman, M.L."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2015,"date_issued":"2015-09-25T22:35:37Z","date_published":"2015-09-25T22:35:37Z","updated_at":"2026-07-22T22:26:24Z","subjects":["Physics, Astronomy and Astrophysics"],"languages":["eng"],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["(MiAaPQ)AAI3202151"],"render_values":[{"text":"(MiAaPQ)AAI3202151","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/85182","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Norman, M.L."]},{"key":"dc:creator","label":"Author","values":["Paschos, Paschalis"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2015-09-25T22:35:37Z","10000-01-01","2005"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Astronomy"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Physics, Astronomy and Astrophysics"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/85182","(MiAaPQ)AAI3202151"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["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). 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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). 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