A Detailed Analysis of a Cygnus Loop Shock-Cloud Interaction
| dc.creator | Danforth, Charles W. | |
| dc.creator | Blair, William P. | |
| dc.creator | Raymond, John C. | |
| dc.date | 2001-04-14 | |
| dc.date.accessioned | 2026-07-07T01:58:13Z | |
| dc.date.available | 2026-07-07T01:58:13Z | |
| dc.description | The XA region of the Cygnus Loop is a complex zone of radiative and nonradiative shocks interacting with interstellar clouds. We combine five far ultraviolet spectral observations from the Hopkins Ultraviolet Telescope (HUT), a grid of 24 IUE spectra and a high-resolution longslit Halpha spectrum to study the spatial emission line variations across the region. These spectral data are placed in context using ground-based, optical emission line images of the region and a far-UV image obtained by the Ultraviolet Imaging Telescope (UIT). The presence of high-ionization ions (OVI, NV, CIV) indicates a shock velocity near 170 km/s while other diagnostics indicate v_shock=140 km/s. It is likely that a large range of shock velocities may exist at a spatial scale smaller than we are able to resolve. By comparing CIV 1550, CIII 977 and CIII] 1909, we explore resonance scattering across the region. We find that a significant column depth is present at all positions, including those not near bright optical/UV filaments. Analysis of the OVI doublet ratio suggests an average optical depth of about unity in that ion while flux measurements of [SiVIII] 1443 suggest a hot component in the region at just below 10^6K. Given the brightness of the OVI emission and the age of the interaction, we rule out the mixing layer interpretation of the UV emission. Furthermore, we formulate a picture of the XA region as the encounter of the blast wave with a finger of dense gas protruding inward from the pre-SN cavity. | |
| dc.description | 21 pages, 9 figures, accepted by the Astronomical Journal, July 2001 Full resolution figures available at http://fuse.pha.jhu.edu/~danforth/xa/ | |
| dc.identifier | https://arxiv.org/abs/astro-ph/0104243 | |
| dc.identifier | http://arxiv.org/abs/astro-ph/0104243 | |
| dc.identifier | Astron.J. 122 (2001) 938 | |
| dc.identifier | doi:10.1086/321161 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/2686 | |
| dc.subject | Astrophysics | |
| dc.title | A Detailed Analysis of a Cygnus Loop Shock-Cloud Interaction | |
| dc.type | text |