A Comparison of Ultraviolet, Optical, and X-Ray Imagery of Selected Fields in the Cygnus Loop

Abstract

During the Astro-1 and Astro-2 Space Shuttle missions in 1990 and 1995, far ultraviolet (FUV) images of five 40' diameter fields around the rim of the Cygnus Loop supernova remnant were observed with the Ultraviolet Imaging Telescope (UIT). These fields sampled a broad range of conditions including both radiative and nonradiative shocks in various geometries and physical scales. In these shocks, the UIT B5 band samples predominantly CIV 1550 and the hydrogen two-photon recombination continuum. Smaller contri- butions are made by emission lines of HeII 1640 and OIII] 1665. We present these new FUV images and compare them with optical Halpha and [OIII], and ROSAT HRI X-ray images. Comparing the UIT images with those from the other bands provides new insights into the spatial variations and locations of these different types of emission. By comparing against shock model calculations and published FUV spectroscopy at select locations, we surmise that resonance scattering in the strong FUV permitted lines is widespread in the Cygnus Loop, especially in the bright optical filaments typically selected for observation in most previous studies.

arXiv comment21 pages with 10 figures. See http://www.pha.jhu.edu/~danforth/uit/ for full-resolution figures

References in corpus (4)

• Panoramic Views of the Cygnus Loop
• The ROSAT-HRI X-Ray Survey of the Cygnus Loop
• The Distance to the Cygnus Loop from Hubble Space Telescope Imaging of the Primary Shock Front
• The Ultraviolet Imaging Telescope: Instrument and Data Characteristics

Cited by in corpus (9)

• Far Ultraviolet Spectra of a Non-Radiative Shock Wave in the Cygnus Loop
• New lambda6cm observations of the Cygnus Loop
• An Isolated, Recently Shocked ISM Cloud in the Cygnus Loop SNR
• A Detailed Analysis of a Cygnus Loop Shock-Cloud Interaction
• Optical and Far-UV Spectroscopy of Knot D in the Vela Supernova Remnant
• Far Ultraviolet Spectroscopic Explorer Survey of Magellanic Cloud Supernova Remnants
• SPEAR Far Ultraviolet Spectral Images of the Cygnus Loop
• Global Far-Ultraviolet Properties of the Cygnus Loop
• Unbiased Spectroscopic Study of the Cygnus Loop with LAMOST. I. Optical Properties of Emission Lines and the Global Spectrum