Comparison of high-resolution radio and optical data for the northeast region of the Cygnus Loop

Journal Article · Tue Jul 01 00:00:00 EDT 1986 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/164340· OSTI ID:7012875

Straka, W C; Dickel, J R; Blair, W P; Fesen, R A

Radio observations of the northeastern part of the Cygnus Loop obtained with the VLA at 18 cm with a resolution of 4.7 arcsec are presented and discussed. In general, the brightest radio filaments match the brightest optical filaments very well, particularly those which are bright in H-alpha. The agreement in position, morphology, and relative brightness is particularly good where all four optical species are bright. However, a few bright radio features have no bright optical counterparts. The general radio and optical structure of the region can be explained by a model in which shocked interstellar clouds form filaments due to unstable cooling and compression. The features appear to be ropelike, although it is not possible to rule out that they are irregular sheets seen edge-on. A large gradation in cooling on a scale of parsecs is evidenced by the sequence of the optical species in emission, with a corresponding increase in density generally evidenced by the continuum radio emission. 19 references.

• Research Organization: Lockheed Research Labs., Palo Alto, CA; Illinois Univ., Urbana; Johns Hopkins Univ., Baltimore, MD; Colorado Univ., Boulder
• OSTI ID: 7012875
• Journal Information: Astrophys. J.; (United States), Vol. 306
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
SUPERNOVA REMNANTS
RADIOWAVE RADIATION
VISIBLE SPECTRA
BALMER LINES
COOLING
MATHEMATICAL MODELS
MORPHOLOGY
NEBULAE
SPECTROSCOPY
COSMIC RADIO SOURCES
ELECTROMAGNETIC RADIATION
RADIATIONS
SPECTRA
640103* - Astrophysics & Cosmology- Quasi-Stellar
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& X-Ray Sources- (-1987)