Radio Recombination Lines

1. Front Matter

   Pages i-x

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2. Physics of Radio Recombination Lines

   1. Front Matter

      Pages 1-1

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   2. Theory of Recombination Lines

      • M. J. Seaton

      Pages 3-22

   3. Laboratory Studies of Rydberg Atoms

      • Daniel Kleppner

      Pages 23-33

3. Radio Recombination Lines from HII Regions

   1. Front Matter

      Pages 35-35

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   2. Interpretation of HII Region Radio Recombination Lines

      • C. M. Walmsley

      Pages 37-51

   3. The Importance of Non-LTE Effects to the Interpretation of Radio Recombination Lines

      • Robert L. Brown

      Pages 53-61

   4. Determination of Electron Temperatures Using Radio Recombination Lines

      • P. A. Shaver

      Pages 63-66

   5. Aperture Synthesis Observations of Recombination Lines from Compact HII Regions

      • J. H. van Gorkom

      Pages 67-73

   6. Radio Recombination Lines from Planetary Nebulae

      • Yervant Terzian

      Pages 75-80

   7. Helium Recombination Lines

      • P. G. Mezger

      Pages 81-97

   8. Systematic Variation of the Helium Ionization in Galactic HII Regions

      • Nino Panagia

      Pages 99-105

   9. Pressure Broadening Effects on the Emission of He Recombination Lines

      • Diego A. Cesarsky

      Pages 107-108

4. Radio Recombination Lines from CII Regions

   1. Front Matter

      Pages 109-109

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   2. The Partially Ionized Medium Adjacent to HII Regions

      • V. Pankonin

      Pages 111-125

   3. Carbon Radio Recombination Line Emission from Dark Clouds

      • Robert L. Brown

      Pages 127-140

   4. Carbon and Sulphur Ionized Regions in Dark Clouds

      • Edith Falgarone

      Pages 141-147

   5. Carbon (?) Recombination Lines in W49a (G43.2-0.0)

      • M. R. Viner, V. A. Hughes

      Pages 149-155

5. Large-Scale Properties of the Galaxy

   1. Front Matter

      Pages 157-157

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   2. The Galactic Center: Results of Radio Recombination Line Surveys

      • T. Pauls

      Pages 159-170

Since their first detection 15 years ago, radio recombination lines from several elements have been observed in a wide variety of objects including HII regions, planetary nebulae, molecular clouds, the diffuse interstellar medium, and recently, other galaxies. The observations span almost the entire range from 0.1 to 100 GHz, and employ both single­ djsh and aperture synthesis techniques. The theory of radio recombination lines has also advanced strongly, to the point where it is perhaps one of the best-understood in astro­ physics. In a parallel development, it has become possible over the last decade to study these same highly-excited atoms in the laboratory; this work provides further confirmation of the theoretical framework. However there has been continuing controversy over the astrophysical interpre­ tation of radio recombination line observations, especially regarding the role of stimulated emission. A workshop was held in Ottawa on 24-25 August, 1979, bringing together many of the active scientists to review the field and discuss these questions of interpretation. A broad concensus has emerged: the subtleties of the line-formation process are understood, and the conditions under which reliable in­ formation can easily be extracted from the line measurements are known. It thus appears likely that the emphasis will shift increasingly from the study of the line phenomenon itself to further application in other areas of astrophysics, ranging from physical processes in plasmas (temperatures, densities, ionization structure), to the large-scale properties of our galaxy (abundances, kinematics, structure), and studies of extragalactic systems.

• Galaxy
• Variation
• astrophysics
• galaxies
• planet
• stellar

• European Southern Observatory, c/o CERN, Geneva 23, Switzerland

  P. A. Shaver

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