Spatial and spectral interpretation of a bright filament in the Cygnus Loop

Journal Article · Fri Jan 01 04:00:00 EST 1988 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/165945· OSTI ID:5275888

Raymond, J C; Hester, J J; Cox, D; Blair, W P; Fesen, R A; Gull, T R

A comparison is made of optical and UV line intensities and spatial and spectral optical line profiles of a well-defined Cygnus Loop filament with theoretical models. It is found that the sharp filament is due to the tangency to the line of sight of a large, thick sheet of emitting gas. The emitting region associated with the spur is very deep, and there is substantial gradient in shock velocity along the filament. Severe incompleteness of the recombination zone is found at the high-velocity end, and resonance scattering in the emitting region attenuates C IV and other resonance lines, as expected. There is evidence for depletion of Si and Fe relative to other elements. Nonthermal pressure apparently dominates the recombination zone of the filament. New techniques are introduced for determining the completeness of a shock and for determining the preshock density without recourse to the standard density diangostic line ratios. 59 references.

• Research Organization: Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (USA); California Institute of Technology, Pasadena (USA); Wisconsin Univ., Madison (USA); Johns Hopkins Univ., Baltimore, MD (USA); Colorado Univ., Boulder (USA)
• OSTI ID: 5275888
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 324; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABUNDANCE
BRIGHTNESS
CHEMICAL COMPOSITION
COMPARATIVE EVALUATIONS
COSMIC GASES
COSMIC RADIO SOURCES
DISTRIBUTION
ENERGY-LEVEL TRANSITIONS
FLUIDS
FORBIDDEN TRANSITIONS
GASES
MATHEMATICAL MODELS
MORPHOLOGY
NEBULAE
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
SHOCK WAVES
SPATIAL DISTRIBUTION
SPECTRA
SUPERNOVA REMNANTS
VISIBLE SPECTRA