{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/22561"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/22561","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"A kinematic and abundance survey in the galactic rotational directions","abstract":"ETDs are only available to UIUC Users without author permission","abstract_html":"ETDs are only available to UIUC Users without author permission","abstract_has_math":false,"creators":["Bell, David James"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Astronomy","degree_department":null,"school":null,"contributors":["Yoss, Kenneth M."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-05-07T13:43:50Z","date_published":"2011-05-07T13:43:50Z","updated_at":"2026-07-22T22:25:20Z","subjects":["Physics, Astronomy and Astrophysics"],"languages":["eng"],"rights":["Copyright 1996 Bell, David James"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["9780591087864","AAI9702460","(UMI)AAI9702460"],"render_values":[{"text":"9780591087864","href":null,"code":true},{"text":"AAI9702460","href":null,"code":true},{"text":"(UMI)AAI9702460","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/22561","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Yoss, Kenneth M."]},{"key":"dc:creator","label":"Author","values":["Bell, David James"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2011-05-07T13:43:50Z","10000-01-01","1996"]},{"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"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 1996 Bell, David James"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/22561","9780591087864","AAI9702460","(UMI)AAI9702460"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["ETDs are only available to UIUC Users without author permission","U of I Only","\"Photometric and spectroscopic observations have been obtained for 1028 G and K-type stars near the cardinal directions corresponding to Galactic rotation and anti-rotation. The spectra have been used to obtain radial velocities by cross-correlation, and estimates of stellar metallicity via a spectrophotometric index. The DDO and BV photometric observations yield estimates of distance, color excess, spectral type and metallicity. Reddening trends as a function of distance are found to be consistent with previous investigations in each of the two directions. An extracted subsample of 570 late-type giants has been used with maximum likelihood modeling to study the kinematic and abundance characteristics of the local Galactic disk. The data are well represented by a two-component disk model in which the \"\"thick disk\"\" has a mean abundance of $-0.35 \\pm 0.06$, an asymmetric drift of $43 \\pm 9$ km s$\\sp{-1}$, and a local normalization of $13 \\pm 3$%. A continuous \"\"extended disk\"\" model is also fitted to the data, but is found to be significantly inferior through a likelihood ratio test.\"","The discrete nature supports disk-formation models in which the thick disk is created by a separate distinguishable process relative to the thin disk, such as through a merger event early in the disk's history. It is less consistent with models in which the thick disk forms through continuous processes, such as during a dissipational disk collapse or through secular kinematic diffusion of stars from a thin-disk configuration into a thick one.","Made available in DSpace on 2011-05-07T13:43:50Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9702460.pdf: 5748371 bytes, checksum: bf81d26c82df6f5f184043e610eea52d (MD5) Previous issue date: 1996","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:58:27Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:27:30-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission"]},{"key":"dc:title","label":"Title","values":["A kinematic and abundance survey in the galactic rotational directions"]}]}],"canonical_facts":{"dc:contributor":["Yoss, Kenneth M."],"dc:creator":["Bell, David James"],"dc:date":["2011-05-07T13:43:50Z","10000-01-01","1996"],"dc:description":["ETDs are only available to UIUC Users without author permission","U of I Only","\"Photometric and spectroscopic observations have been obtained for 1028 G and K-type stars near the cardinal directions corresponding to Galactic rotation and anti-rotation. The spectra have been used to obtain radial velocities by cross-correlation, and estimates of stellar metallicity via a spectrophotometric index. The DDO and BV photometric observations yield estimates of distance, color excess, spectral type and metallicity. Reddening trends as a function of distance are found to be consistent with previous investigations in each of the two directions. An extracted subsample of 570 late-type giants has been used with maximum likelihood modeling to study the kinematic and abundance characteristics of the local Galactic disk. The data are well represented by a two-component disk model in which the \"\"thick disk\"\" has a mean abundance of $-0.35 \\pm 0.06$, an asymmetric drift of $43 \\pm 9$ km s$\\sp{-1}$, and a local normalization of $13 \\pm 3$%. A continuous \"\"extended disk\"\" model is also fitted to the data, but is found to be significantly inferior through a likelihood ratio test.\"","The discrete nature supports disk-formation models in which the thick disk is created by a separate distinguishable process relative to the thin disk, such as through a merger event early in the disk's history. It is less consistent with models in which the thick disk forms through continuous processes, such as during a dissipational disk collapse or through secular kinematic diffusion of stars from a thin-disk configuration into a thick one.","Made available in DSpace on 2011-05-07T13:43:50Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9702460.pdf: 5748371 bytes, checksum: bf81d26c82df6f5f184043e610eea52d (MD5) Previous issue date: 1996","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:58:27Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:27:30-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission"],"dc:identifier":["http://hdl.handle.net/2142/22561","9780591087864","AAI9702460","(UMI)AAI9702460"],"dc:language":["eng"],"dc:rights":["Copyright 1996 Bell, David James"],"dc:subject":["Physics, Astronomy and Astrophysics"],"dc:title":["A kinematic and abundance survey in the galactic rotational directions"],"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":"2026-07-22T22:25:20Z"}