{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/70659"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/70659","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Global and Local Properties of Noninteracting Irregular Galaxies","abstract":"In order to investigate the star formation processs controlling the evolutionary histories of noninteracting irregular galaxies, we have obtained optical and radio data on global and local scales for a sample of 26 irregulars with high star formation rates (SFR) and 17 comparison objects. Global properties of the systems were explored through the stellar and gaseous contents and abundances obtained from intermediate band filter photometry, large aperture spectrophotometry, small aperture spectrophotometry of individual H II regions, and H I 21-cm observations. The gas and abundance parameters, combined with other derived quantities such as the SFR, the fraction of a galaxy involved in the current star forming activity, and the time scale to exhaust the gas, were compared to predictions of global models of galaxy evolution: the closed system, stochastic star induced star formation, and gas infall models. In addition, large-aperture spectra of a sample of low-luminosity irregulars were obtained which provided a comparison to dwarf systems with low rates of star formation.","abstract_html":"In order to investigate the star formation processs controlling the evolutionary histories of noninteracting irregular galaxies, we have obtained optical and radio data on global and local scales for a sample of 26 irregulars with high star formation rates (SFR) and 17 comparison objects. Global properties of the systems were explored through the stellar and gaseous contents and abundances obtained from intermediate band filter photometry, large aperture spectrophotometry, small aperture spectrophotometry of individual H II regions, and H I 21-cm observations. The gas and abundance parameters, combined with other derived quantities such as the SFR, the fraction of a galaxy involved in the current star forming activity, and the time scale to exhaust the gas, were compared to predictions of global models of galaxy evolution: the closed system, stochastic star induced star formation, and gas infall models. In addition, large-aperture spectra of a sample of low-luminosity irregulars were obtained which provided a comparison to dwarf systems with low rates of star formation.","abstract_has_math":false,"creators":["Hunter, Deidre Ann"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Astronomy","degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2014,"date_issued":"2014-12-16T00:55:12Z","date_published":"2014-12-16T00:55:12Z","updated_at":"2026-07-22T22:26:03Z","subjects":["Physics, Astronomy and Astrophysics"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["(UMI)AAI8302891"],"render_values":[{"text":"(UMI)AAI8302891","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/70659","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Hunter, Deidre Ann"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2014-12-16T00:55:12Z","10000-01-01","1982"]},{"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":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/70659","(UMI)AAI8302891"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["In order to investigate the star formation processs controlling the evolutionary histories of noninteracting irregular galaxies, we have obtained optical and radio data on global and local scales for a sample of 26 irregulars with high star formation rates (SFR) and 17 comparison objects. Global properties of the systems were explored through the stellar and gaseous contents and abundances obtained from intermediate band filter photometry, large aperture spectrophotometry, small aperture spectrophotometry of individual H II regions, and H I 21-cm observations. The gas and abundance parameters, combined with other derived quantities such as the SFR, the fraction of a galaxy involved in the current star forming activity, and the time scale to exhaust the gas, were compared to predictions of global models of galaxy evolution: the closed system, stochastic star induced star formation, and gas infall models. In addition, large-aperture spectra of a sample of low-luminosity irregulars were obtained which provided a comparison to dwarf systems with low rates of star formation.","The investigation of the emission regions was based on measurements of local ionized gas kinematics through high dispersion spectra and on explorations of the spatial structure and distribution of star forming regions from direct imaging with a video camera through b,y,I, and H(alpha) passbands. These data were used to estimate the mechanical energy that is being returned to the interstellar medium from massive stars in the form of motions of ionized gas, diameters of distinct star forming regions, distances between H II regions, and the presence of dark clouds. These results were used to place constraints on the global star formation mechanisms in space and time and were compared to models for propagation of star formation. The results on both global and local scales were used to develop a general picture of the evolutionary histories of irregular galaxies.","Made available in DSpace on 2014-12-16T00:55:12Z (GMT). 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Global properties of the systems were explored through the stellar and gaseous contents and abundances obtained from intermediate band filter photometry, large aperture spectrophotometry, small aperture spectrophotometry of individual H II regions, and H I 21-cm observations. The gas and abundance parameters, combined with other derived quantities such as the SFR, the fraction of a galaxy involved in the current star forming activity, and the time scale to exhaust the gas, were compared to predictions of global models of galaxy evolution: the closed system, stochastic star induced star formation, and gas infall models. In addition, large-aperture spectra of a sample of low-luminosity irregulars were obtained which provided a comparison to dwarf systems with low rates of star formation.","The investigation of the emission regions was based on measurements of local ionized gas kinematics through high dispersion spectra and on explorations of the spatial structure and distribution of star forming regions from direct imaging with a video camera through b,y,I, and H(alpha) passbands. These data were used to estimate the mechanical energy that is being returned to the interstellar medium from massive stars in the form of motions of ionized gas, diameters of distinct star forming regions, distances between H II regions, and the presence of dark clouds. These results were used to place constraints on the global star formation mechanisms in space and time and were compared to models for propagation of star formation. The results on both global and local scales were used to develop a general picture of the evolutionary histories of irregular galaxies.","Made available in DSpace on 2014-12-16T00:55:12Z (GMT). No. of bitstreams: 1 8302891.pdf: 9126792 bytes, checksum: 25674519b487e2fa19e1b9fa3d88509b (MD5) Previous issue date: 1982","Embargo set by: Seth Robbins for item 70825 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","281 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1982."],"dc:identifier":["http://hdl.handle.net/2142/70659","(UMI)AAI8302891"],"dc:subject":["Physics, Astronomy and Astrophysics"],"dc:title":["Global and Local Properties of Noninteracting Irregular Galaxies"],"dc:type":["text"],"thesis:degree_discipline":["Astronomy"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:26:03Z"}