HII regions in absorption at low frequencies

  • Namir E. Kassmim
IV. Sne, SNRs, and Ionized Gas in the Interstellar Medium
Part of the Lecture Notes in Physics book series (LNP, volume 362)


This paper reviews the information provided by the analysis of low radio frequency (v<100 MHz) observations of HII regions seen in absorption against the Galactic background radiation. We show how such observations can be used to constrain various physical parameters associated with the Galactic background and the HII regions. The technique is illustrated by analysis of 30.9 MHz observations of the W51 giant HII complex. The importance of obtaining observations made at more than one low frequency is emphasized.


Brightness Temperature Recombination Line High Frequency Data Galactic Magnetic Field Galactic Longitude 
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.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Altenhoff, W.J., Downes, D., Pauls, T., and Schraml, J. 1978, Astr. Ap. Suppl., 35, 23.Google Scholar
  2. Bieging, J. 1975, in “HII Regions and Related Topics”, eds. T.L. Wilson and D. Downes, (Berlin:Springer), pg. 443.Google Scholar
  3. Bridle, A. H. 1967, M.N.R.A.S., 136, 219.Google Scholar
  4. Cane, H.V. 1978, Aust. J. Phys., 31, 561.Google Scholar
  5. Deshpande, A.A. and Sastry, C.V. 1986, Astr. Astrophys., 160, 129.Google Scholar
  6. Downes, D., Wilson, T.L., Beiging, J., and Wink, J. 1980, Astr. Ap. Suppl., 40, 379.Google Scholar
  7. Dulk, G.A. and Slee, O.B. 1972, Australian J. Phys., 25, 429.Google Scholar
  8. Dulk, G.A. and Slee, O.B. 1975, Ap. J., 199, 61.CrossRefGoogle Scholar
  9. Kassim, N.E. 1987, Ph.D. thesis, University of Maryland.Google Scholar
  10. Kassim, N.E. 1988, Ap. J. Suppl., 68, 715.CrossRefGoogle Scholar
  11. Kassim, N.E. 1989, Ap. J., 347, 915.Google Scholar
  12. Kassim, N.E. and Weiler, K.W. 1990, Nature, 343, 146.CrossRefGoogle Scholar
  13. Longair, M.S. 1990, in these proceedingsGoogle Scholar
  14. Milogradov-Turin, J. 1974, Mem. Soc. Astron. Ital., 45, 85.Google Scholar
  15. Milogradov-Turin, J. and Smith, F.G. 1974, M.N.R.A.S., 161, 269.Google Scholar
  16. Parrish, A. 1972, Astron. J., 174, 33.Google Scholar
  17. Reynolds, R.J. 1990, in these proceedings.Google Scholar
  18. Webber, W.R. 1990, in these proceedings.Google Scholar
  19. Wink, J.E., Wilson, T.L., and Beiging, J.H. 1983, Astr. Ap., 127, 211.Google Scholar

Copyright information

© Springer-Verlag 1990

Authors and Affiliations

  • Namir E. Kassmim
    • 1
  1. 1.ONT Postdoctoral Fellow Center for Advanced Space SensingNaval Research LaboratoryWashington

Personalised recommendations