The Interstellar Disk-Halo Connection in Galaxies

ISBN-13: 9780792312550 / Angielski / Twarda / 1991 / 454 str.

International Astronomical Union; Hans Bloemen

Opis

Highly ionized atoms in the general interstellar gas of the galactic disk were first detected through interstellar absorption line observations of 0 VI with the Copernicus satellite (Rogerson et al. 1973). Survey measurements by Jenkins (1978) of interstellar 0 VI absorption toward 72 stars demonstrated the general presence of 0 VI in the interstellar medium of the galactic disk. This researcIi. and parallel observational studies of the soft X-ra}' background (Williamson et al. 1974; McCammon et al. 1983; Marshall and ClarK 1984) provided direct evidence for the existence of hot low density gas in the mterstellar medium of the galactic disk. The extension of the aDsorption line studies to the distant gas of the galactic halo required the launch of the International Ultraviolet Explorer (IUE) satellite in 1978. The first measures of highly ionized gas m the galactic halo were obtained with the IDE when it was used to record high resolution spectra of bright stars in the Large Magellanic Cloud (Savage and de Boer 1979). Those early spectra revealed the presence of absorption by Si IV and C IV in the galactic nalo and have been followed by a number of surveys with IUE of nighly ionized gas in the galactic disk and halo (Savage and de Boer 1981; Pettini and West 1982; Savage and Massa 1987). The study of UV emission from highly ionized gas in the halo has progressed more slowly because of the intrinsic faintness of the emission.

Spis treści

to Fountains, Wind, Infall (and Magnetic Fields and Dynamo Mechanisms).- I. The Disk-Halo Interface in Our Galaxy.- The Neutral Halo in the Inner Galaxy.- High-velocity Clouds.- Molecular Clouds at High z.- Optical and Ultraviolet Absorption Studies of Cool Gas in the Milky Way Halo.- Ionized Disk/Halo Gas: Insight from Optical Emission Lines and Pulsar Dispersion Measures.- Dark Matter Decay and the Heating and Ionisation of HI Regions.- Constraints on Galactic Infall from Studies of Chemical Evolution.- Infall of HVC’s and the Origin of HI Supershells.- Wave Structure within HI Filaments at High Galactic Latitude and the Nature of “Clouds” in Interstellar Space.- The Stellar Disk-Halo Connection.- Star Formation at Large Galactic z?.- Molecular Clouds and Star Formation at Large R.- UV Absorption and Emission Lines from Highly Ionized Gas in the Galactic Halo.- Hot Gas in the Disk, Halo, and Disk-Halo Interaction.- The High-Latitude Sky at IR, Optical, and UV Wavelengths.- Metals and Molecules in Halo Clouds.- Galactic Worms.- Magnetic Fields in the Disk-Halo Interface.- The Cosmic-ray Halo: Insight from Gamma Rays and Cosmic-ray Observations.- Radio Studies of Cosmic Rays in the Galaxy.- Ionization in the Interstellar HI Region by Low-energy Cosmic-ray Electrons (poster).- Optical Radiation Field in the Disk and Halo (poster).- II. The Disk-Halo Interface in Other Galaxies.- Large-scale Structure of HI in other Galaxies.- Small-scale Properties of HI in Nearby Galaxies.- Diffuse Ionized Gas in Nearby Galaxies.- Is there Evidence for Disk-Halo Connections in M31?.- X-ray Haloes and Cooling Flows.- Opaque Spiral Disks: Some Empirical Facts and Consequences.- Radio Studies of Cosmic Rays in Nearby Galaxies.- Magnetic Fields in Disks and Halos of Spiral Galaxies.- Synchrotron Emission as a Tracer of the Outflow in M82.- NGC 891: A Summary of Observations.- The Diffuse Ionized Gas Perpendicular to the Plane of NGC 891.- A CO survey of the Halo of NGC 891.- Cool Ionized Gas in Galaxy Thick Disks.- Slow Rotation of Gas in the Halos of Edge-on Galaxies M82 and NGC 4631 (poster).- Boiling-Steaming Galactic Disk: Vertical Dust Jets in the Disk-Halo Interface (poster).- III. Theory and Modelling.- The Galactic Gravitational Potential.- Hydrostatic Equilibrium of the Gas-Field System in the Galaxy and its Stability.- Some Problems for Galactic Hydrostatic Equilibria.- The Global Mass, Energy, and Photoionization Balance of the Disk-Halo Interaction.- Cosmic-ray–powered Fountains and Winds.- The X-ray Appearance of Supernova Remnants in Tenuous Media.- Static versus Dynamical Cosmic-ray Halos.- The Influence of Extended Source Distributions on Cosmic-ray Spectral Index Variations in the Galactic Wind Model.- Dynamical Implications of Diffusive and Convective Cosmic-ray Propagation in Galactic Halos.- Particle Acceleration in the Disk-Halo System.- The Structure of the Interstellar Medium.- Grain Evolution in the Framework of Disk-Halo Interactions.- Numerical Simulations of Galactic Outflow and Inflow Phenomena.- Large-scale Gas Dynamical Processes Affecting the Origin and Evolution of Gaseous Galactic Halos.- Nonlinear Evolution of the Parker Instability.- Rapporteur Papers.- The Interstellar Disk-Halo Connection in Galaxies: Review of Observational Aspects.- poster book.- Author index.