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Dufour, Reginald J. Clayton, Donald W. Few, Arthur A. Hester, John Jeffrey 2018-12-18T21:15:02Z 2018-12-18T21:15:02Z 1983 Hester, John Jeffrey. "Digital analysis of narrow band imagery of the Cygnus loop." (1983) Master’s Thesis, Rice University. <a href="https://hdl.handle.net/1911/103892">https://hdl.handle.net/1911/103892</a>. https://hdl.handle.net/1911/103892 RICE1518 Thesis Sp. Sci. 1983 Hester 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 . 88 pp reformatted digital eng 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. Digital analysis of narrow band imagery of the Cygnus loop Thesis Text Space Science Natural Sciences Rice University Masters Master of Science open.access