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Observations of O VI

  • Edward B. Jenkins
Part of the Astrophysics and Space Science Library book series (ASSL, volume 70)

Abstract

A useful spectroscopic tracer for a hot phase of interstellar gas is the O VI ion, which reaches its maximum concentration in collisional ionization between 105 and 106 K. Presently, over 70 stars have been observed for O VI absorption by the Copernicus satellite. Nearly all of the stars show broad, weak lines, but no evidence favoring a circumstellar origin for the gas can be found. An overall average for ne of the hot gas in the galactic plane is of order 10−3 cm−3. The relative volume in space occupied by the hot gas regions (and hence their internal density) is uncertain, but a filling factor in the range 0.02 to 0.2 seems most plausible. Fluctuations in radial velocities and column densities suggest there are roughly 6 regions per kpc, each with N(0 VI) ≈ 1013 cm−2. The observed rms dispersion of radial velocities for these regions is 26 km s−1.

Keywords

Radial Velocity Column Density Galactic Plane Supernova Remnant Circumstellar Shell 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© D. Reidel Publishing Company, Dordrecht, Holland 1977

Authors and Affiliations

  • Edward B. Jenkins
    • 1
  1. 1.Princeton University ObservatoryUSA

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