{"id":{"repo_id":"rice","oai_identifier":"oai:repository.rice.edu:1911/103892"},"canonical_url":"https://search.dev.ndltd.org/etd/rice/oai:repository.rice.edu:1911/103892","repository":{"repo_id":"rice","name":"Rice University","base_url":"https://repository.rice.edu/server/oai/request"},"display":{"title":"Digital analysis of narrow band imagery of the Cygnus loop","abstract":"Digital analysis of narrow passband direct imagery of a field in the southeast part of the Cygnus Loop SNR is presented. Calibrated surface brightness and spectral line ratio maps involving emission lines from six different ionic species are shown. The detailed morphology of the remnant and correlations between various line ratios are discussed in the context of recent shock model calculations. The spatial structure is categorized on the basis of the presence or absence of features in images isolating different emission lines, and the correlation or lack thereof between these features and features in the maps of spectral line ratios such as [ III] 57/Ha. For a common type of structure, features present in line ratio maps are not associated with surface brightness features. These same structures also demonstrate spectral behavior consistent with that predicted by steadyflow shock calculations, indicating the presence of steady-flow shocks with velocities from <= 6 km/sec to ≈ 12 km/sec. Differences in the morphologies of the remnant as viewed in different emission lines and gradients in spectral line ratios are interpreted as a continuous transition with distance behind the blast wave from non-steady-flow shocks with velocities >= 13 km/sec to steady-flow shocks with velocities ≈ 6 km/sec .","abstract_html":"Digital analysis of narrow passband direct imagery of a field in the southeast part of the Cygnus Loop SNR is presented. Calibrated surface brightness and spectral line ratio maps involving emission lines from six different ionic species are shown. The detailed morphology of the remnant and correlations between various line ratios are discussed in the context of recent shock model calculations. The spatial structure is categorized on the basis of the presence or absence of features in images isolating different emission lines, and the correlation or lack thereof between these features and features in the maps of spectral line ratios such as [ III] 57/Ha. For a common type of structure, features present in line ratio maps are not associated with surface brightness features. These same structures also demonstrate spectral behavior consistent with that predicted by steadyflow shock calculations, indicating the presence of steady-flow shocks with velocities from <= 6 km/sec to ≈ 12 km/sec. Differences in the morphologies of the remnant as viewed in different emission lines and gradients in spectral line ratios are interpreted as a continuous transition with distance behind the blast wave from non-steady-flow shocks with velocities >= 13 km/sec to steady-flow shocks with velocities ≈ 6 km/sec .","abstract_has_math":false,"creators":["Hester, John Jeffrey"],"institution":"Rice University","degree_name":"Master of Science","degree_level":"Masters","degree_discipline":"Natural Sciences","degree_department":null,"school":null,"contributors":[],"advisors":["Dufour, Reginald J."],"committee_chairs":[],"committee_members":["Clayton, Donald W.","Few, Arthur A."],"year":1983,"date_issued":"1983","date_published":"1983","updated_at":"2026-07-24T04:10:17Z","subjects":[],"languages":["eng"],"rights":["Copyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder."],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/1911/103892","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Dufour, Reginald J."]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Clayton, Donald W.","Few, Arthur A."]},{"key":"dc:creator","label":"Author","values":["Hester, John Jeffrey"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2018-12-18T21:15:02Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2018-12-18T21:15:02Z"]},{"key":"dc:date.issued","label":"Date","values":["1983"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Natural Sciences"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Masters"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Rice University"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder."]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://hdl.handle.net/1911/103892"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Digital analysis of narrow passband direct imagery of a field in the southeast part of the Cygnus Loop SNR is presented. Calibrated surface brightness and spectral line ratio maps involving emission lines from six different ionic species are shown. The detailed morphology of the remnant and correlations between various line ratios are discussed in the context of recent shock model calculations. The spatial structure is categorized on the basis of the presence or absence of features in images isolating different emission lines, and the correlation or lack thereof between these features and features in the maps of spectral line ratios such as [ III] 57/Ha. For a common type of structure, features present in line ratio maps are not associated with surface brightness features. These same structures also demonstrate spectral behavior consistent with that predicted by steadyflow shock calculations, indicating the presence of steady-flow shocks with velocities from <= 6 km/sec to ≈ 12 km/sec. Differences in the morphologies of the remnant as viewed in different emission lines and gradients in spectral line ratios are interpreted as a continuous transition with distance behind the blast wave from non-steady-flow shocks with velocities >= 13 km/sec to steady-flow shocks with velocities ≈ 6 km/sec ."]},{"key":"dc:title","label":"Title","values":["Digital analysis of narrow band imagery of the Cygnus loop"]}]}],"canonical_facts":{"dc:contributor.advisor":["Dufour, Reginald J."],"dc:contributor.committeemember":["Clayton, Donald W.","Few, Arthur A."],"dc:creator":["Hester, John Jeffrey"],"dc:date.accessioned":["2018-12-18T21:15:02Z"],"dc:date.available":["2018-12-18T21:15:02Z"],"dc:date.issued":["1983"],"dc:description.abstract":["Digital analysis of narrow passband direct imagery of a field in the southeast part of the Cygnus Loop SNR is presented. Calibrated surface brightness and spectral line ratio maps involving emission lines from six different ionic species are shown. The detailed morphology of the remnant and correlations between various line ratios are discussed in the context of recent shock model calculations. The spatial structure is categorized on the basis of the presence or absence of features in images isolating different emission lines, and the correlation or lack thereof between these features and features in the maps of spectral line ratios such as [ III] 57/Ha. For a common type of structure, features present in line ratio maps are not associated with surface brightness features. These same structures also demonstrate spectral behavior consistent with that predicted by steadyflow shock calculations, indicating the presence of steady-flow shocks with velocities from <= 6 km/sec to ≈ 12 km/sec. Differences in the morphologies of the remnant as viewed in different emission lines and gradients in spectral line ratios are interpreted as a continuous transition with distance behind the blast wave from non-steady-flow shocks with velocities >= 13 km/sec to steady-flow shocks with velocities ≈ 6 km/sec ."],"dc:identifier.uri":["https://hdl.handle.net/1911/103892"],"dc:language.iso":["eng"],"dc:rights":["Copyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder."],"dc:title":["Digital analysis of narrow band imagery of the Cygnus loop"],"dc:type":["Thesis"],"thesis:degree_discipline":["Natural Sciences"],"thesis:degree_level":["Masters"],"thesis:degree_name":["Master of Science"],"thesis:institution_name":["Rice University"]},"updated_at":"2026-07-24T04:10:17Z"}