This work deals with some of the most typical complexes of interstellar matter and is intended to serve both as a reference book for the specialist and as an introduction for the newcomer to the field. It is hoped to meet the first aim by presenting a holistic view of the well studied complexes in Orion, built on information derived from various branches of modern Astrophysics. The wealth of published data is presented in the form of photographs, contour maps, diagrams and numerous heavily annotated tables. The second aim is pursued by providing an outline of the complexes, the physical problems associated with them, the empirical models describing their be haviour and, in addition, by including an extended Appendix section summarizing the numerous methods employed to derive the physical parameters of an H II region and the dust and molecular cloud physically associated with it. The book consists of five chapters and four Appendix sections. Chapter 1, which is concerned with the large scale view of the Orion region, outlines the morphology of the area and examines in particular the nature of Barnard's Loop and the associated filamentary structure in addition to the origin of the I Orion OB association. Chapter 2 focuses on the ionized gas of the Orion H II/molecular complex i. e.

Inhalt

1: Large Scale View of the Orion Region.- 1.1. General Morphology of Barnard's Loop and the Neighbouring Region.- 1.2. Nature of Barnard's Loop and the Associated Filamentary Structure.- 1.3. Origin of the I Orion OB Association.- Tables.- Figures.- 2: The H II Regions M42 and M43.- 2.1. Optical and Radio Structure.- 2.2. Physical Parameters Derived from Radio and Optical Observations.- 2.3. Ionized Stellar-Size Condensations (ISC) and Ionized Knots (IK) Associated with the Core of M42.- 2.4. Dust in the Orion Nebula (M42).- Tables.- Figures.- 3: The Orion Complex (M42/OMC1, M43/OMC2).- 3.1. Infrared Structure.- 3.2. Physical Parameters Derived from Infrared Observations.- 3.3. Structure and Physical Parameters of the Molecular Complex (OMC 1, OMC 2).- 3.4. Maser Sources.- 3.5. Magnetic Field in the Orion Complex.- Tables.- Figures.- 4: Empirical Models of the Orion Complex.- 4.1 Empirical Models.- Tables.- Figures.- 5: NGC2024 and the Associated Molecular Complex.- 5.1. Optical and Radio Structure of NGC2024.- 5.2. Infrared and Molecular Structure of the NGC2024/Molecular Complex.- 5.3. Excitation of NGC2024.- Tables.- Figures.- Appendices.- Appendix I: Radiative Transfer.- I. 1. The Various Forms of the Equation of Radiative Transfer.- Figure.- Appendix II: Physical Parameters of an H II Region.- II. 1. Physical Parameters Derived from Observations of the Radio Continuum Emission.- II. 2. Determination of Density from Optical Methods.- II. 3. Determination of Temperature from Optical and Radio Methods.- II. 4. Chemical Composition.- II. 5. Determination of Radial Velocity and Turbulence.- Tables.- Figures.- Appendix III: Physical Parameters of the Dust Associated With an H II Region.- III. 1. Visual Extinction Derived from the Comparison of Optical with Radio Data.- III. 2. Physical Parameters Derived from Observations of the Infrared Continuum.- Figures.- Appendix IV: Physical Parameters of a Molecular Cloud.- IV. 1. Physical Parameters Derived from Observations of Molecular Lines.- References.