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Optical Emission Line Studies and the Warm Ionized Component of the Local Interstellar Medium

Published online by Cambridge University Press:  12 April 2016

R.J. Reynolds
R.J. Reynolds*
Affiliation:
Physics Department, University of Wisconsin-Madison

Abstract

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Observations of diffuse, galactic Hα, [NII]λ6583, and [SII]λ6716 emission lines provide evidence for a warm (~ 104 K), primarily ionized component of the interstellar medium distributed throughout the galactic disk. This component of the interstellar gas has an electron density ≈ 0.1-0.2 cm-3 and occupies about 10-30% of the interstellar volume. Interstellar Hα emission near the galactic poles, the dispersion measure of a nearby pulsar, and observations of interstellar gas flowing into the solar system indicate that this ionized component is an important constituent of the interstellar medium in the solar neighborhood. The intensity of the Hα background at high galactic latitudes implies that this component is maintained by an average hydrogen ionization rate in the vicinity of the Sun of (2-4) x 106 s-1 per cm2 of galactic disk. The emission measure is 1.3-2.3 cm-6 pc toward the galactic poles. The sources of this ionization have not yet been identified but may include escaping Lyman continuum radiation from planetary nebulae, hot white dwarfs, and early type stars. Investigations of the regions surrounding ζ Oph (09V), the nearest (d ≃ 140 pc) 0 star, and a Vir (Bl IV), one of the nearest (d ≃ 87 pc) early B stars, have revealed areas of enhanced Hα emission extending 6°-12° from each star. However, it appears that these stars do not contribute significantly to the more diffuse ionization within the local interstellar medium.

Type
The LISM at Optical Wavelengths: Spectral Line Studies
Information
International Astronomical Union Colloquium , Volume 81: Local Interstellar Medium , 1984 , pp. 95 - 108
Copyright
Copyright © NASA 1984

References

Abbott, D. C. 1982, Ap. J., 263, 723.Google Scholar
Backer, D. C., and Sramek, R.A. 1982, Ap. J., 260, 512.Google Scholar
Bobroff, N., Nousek, J., and Garmire, G. 1984, Ap. J., 277, 678.Google Scholar
Bridle, A. H., and Venugopal, V. R. 1969, Nature, 224, 545.CrossRefGoogle Scholar
Chevalier, R. A. 1974, Ap. J., 188, 501.Google Scholar
Ellis, G. R. A. 1982, Aust. J. Phys., 35, 91.CrossRefGoogle Scholar
Frisch, P. C., and York, D. G. 1983, Ap. J.(Letters), 271, L59.CrossRefGoogle Scholar
Gwinn, C. R., Taylor, J. H., Weisberg, J. M., and Rawley, L. A. 1984, IAU Colloquium No. 81.Google Scholar
Harding, D. S., and Harding, A. K. 1982, Ap. J., 257, 603.Google Scholar
Hills, J. G. 1972, Astr. Ap., 17, 155.Google Scholar
Jura, M. 1979, Ap. J., 227, 798.Google Scholar
Manchester, R. N., and Taylor, J. H. 1981, Ap. J., 86, 1953.Google Scholar
McCammon, D., Burrows, D. N., Sanders, W. T., and Kraushaar, W. L. 1983, Ap. J., 269, 107.Google Scholar
McKee, C. F., and Ostriker, J. P. 1977, Ap. J., 218, 148.CrossRefGoogle Scholar
Panagia, N. 1973, A. J., 78, 929.Google Scholar
Paresce, F. 1984, preprint No. 15, Space Telescope Science Institute.Google Scholar
Paresce, F., and Jakobsen, P. 1980, Nature, 288, 119.CrossRefGoogle Scholar
Parker, R. A. R., Gull, T. R., and Kirshner, R. P. 1979, An Emission Line Survey of the Milky Way (NASA SP-434).Google Scholar
Pengelly, R. M. 1964, MNRAS, 127, 145.CrossRefGoogle Scholar
Readhead, A. C. S., and Duffett-Smith, P. J. 1975, Astr. Ap., 42, 151.Google Scholar
Reynolds, R. J. 1976a, Ap. J., 203, 151.Google Scholar
Reynolds, R. J. 1976b, Ap. J., 206, 679.Google Scholar
Reynolds, R. J. 1977, Ap. J., 216, 433.Google Scholar
Reynolds, R. J. 1980, Ap. J., 236, 153.Google Scholar
Reynolds, R. J. 1981, in The Phases of the Interstellar Medium: Proceedings of a Workshop held at the National Radio Astronomy Observatory, Green Bank, West Virginia, May 10–13, 1981, ed. Dickey, J. M., p. 109.Google Scholar
Reynolds, R. J. 1983, Ap. J., 268, 698.Google Scholar
Reynolds, R. J. 1984a, Ap. J.. (July 1).Google Scholar
Reynolds, R. J., and Ogden, P. M. 1979, Ap. J., 229, 942.Google Scholar
Reynolds, R. J., and Ogden, P. M. 1982, A. J., 87, 306.Google Scholar
Reynolds, R. J., Roesler, F. L., and Scherb, F. 1977, Ap. J., 211, 115.Google Scholar
Reynolds, R. J., Scherb, F., and Roesler, F. L. 1973, Ap. J., 185, 869.CrossRefGoogle Scholar
Reynolds, R. J., and Shih, P. 1983, B.A.A.S., 14, 892; in preparation.Google Scholar
Roesler, F. L., Reynolds, R. J., Scherb, F., and Ogden, P. M. 1978, High Resolution Spectroscopy: Proceedings of the Fourth Colloquium on Astrophysics of the Trieste Observatory, ed. Hack, M., p. 600.Google Scholar
Salpeter, E. E. 1978, in IAU Symposium No. 76, Planetary Nebulae, ed. Terzian, Y. (Dordrecht: Reidel), p. 333.Google Scholar
Salter, M. J., Lyne, A. G., and Anderson, B. 1979, Nature, 280, 477.Google Scholar
Shull, J. M. 1979, Ap. J., 234, 761.Google Scholar
Sivan, J. P. 1974, Astr. Ap. Suppl., 16, 163.Google Scholar
Spitzer, L., and Jenkins, E. B. 1975, Ann. Rev. Astr. Ap., 13, 133.Google Scholar
Taylor, J. H., and Manchester, R. N. 1977, Ap. J., 215, 885.Google Scholar
Terzian, Y. 1974, Ap. J., 193, 93.Google Scholar
Torres-Peimbert, S., Lazcano-Araujo, A., and Peimbert, M. 1974, Ap. J., 191, 401.Google Scholar
Weller, C. S., and Meier, R. R. 1981, Ap. J., 246, 386.Google Scholar
Weisberg, J. M., Rankin, J., and Boriakoff, V. 1980, Astr. Ap., 88, 84.Google Scholar
York, D. G. 1982, Ann. Rev. Astr. Ap., 20, 221.CrossRefGoogle Scholar
York, D. G. 1983, Ap. J., 264, 172.CrossRefGoogle Scholar