Titel: Galactic and Intergalactic Magnetic Fields
Proceedings of the 140th Symposium of the International Astronomical Union Held in Heidelberg, F. R. G. , June 19-23, 1989.
'International Astronomical Union Symposia'.
Herausgegeben von R. Beck, P. P. Kronberg, R. Wielebinski
30. April 1990 - gebunden - 574 Seiten
This Symposium, the first devoted entirely to the measurement and the role of magnetic fields in the non-solar Universe, was held in Heidelberg, on June 19-23, 1989. The meeting began with review talks on magnetic phenomena near the solar photosphere, corona, and in stellar winds, since these nearby "laboratories", studied for many years, provide much of the prior knowl edge of magnetic effects in astrophysical plasmas. The Symposium contained presentations of considerable new work concerning the role of magnetic fields in accretion disks, bipolar outflows, and related magnetic phenomena in molecular clouds and star forming regions. Both observa tions and related theory of the large-scale magnetic fields in the Milky Way were covered, in addition to a session on the more general theme of magnetohydrodynamics of galactic magnetic fields. Dynamo mechanisms were discussed in considerable detail. It was apparent that recent observational data on polarized emission from external galaxies are now of sufficiently high quality that meaningful tests of large-scale field amplification, and of ideas on the origin of galactic magnetic fields, can be undertaken. Both new observations and numerical simulation work were described in the context of active galaxy nuclei, supernova remnants, radio source jets and extended lobes, and also in the environment of galaxy clusters. Recent large-scale computer simulations incorporating magnetic fields in star formation, radio source jets, and many other phenomena were presented, and much of this was very new.
1. A Survey of Magnetic Phenomena near the Solar Photosphere, in the Corona, and in Stellar Winds.- The Magnetic Field of the Sun: An Object Lession.- The Dynamics of Solar Coronal Magnetic Fields.- Solar Coronal Mass Ejections.- A Storage Process of the Magnetic Energy in the Space Active Regions and Stellar Atmosphere.- CoMStOC: The Coronal Magnetic Structures Observing Campaign.- Masers and Stellar Magnetic Fields.- Magnetized Langmuir Solitons Around Pulsars.- Magnetic Field of Rotating Bodies.- 2. The Magnetic Field Structure of the Milky Way: The Meeting of Observation and Theory.- The Magnetic Field of the Milky Way.- A Survey of Recent Magnetic Field Measurements in HI Features of the Galaxy.- Pulsars as Probes of the Galactic Magnetic Field.- Structure of the Local Galactic Magnetic Field.- A Faraday Rotation Survey in the First Quadrant of the Galaxy.- Parameters of the Magnetic Field in the Local Galactic Arm Derived from Low Frequency Absorption Measurements in the Ionized Gas.- The Two Component Magnetic Field of the Galaxy.- Fluctuations in the Galactic Magnetic Field.- Correlation Between Galactic Non-Thermal Continuum Emission and HI-Column Density.- A Detailed Model of the Distribution of Synchrotron Emission in the Galactic Disk.- The Need for High Resolution for Polarization Studies of Galactic Background Radiation.- Extended Polarized Emission Structures in the Galactic Plane at 11 cm Wavelength.- The Magnetic Field of the Galaxy in the Solar Vicinity and the Polarization of Stars.- 3. Magnetic Fields in and around Supernova Remnants.- Polarization and Magnetic Fields in Supernova Remnants.- Probing the Interstellar Magnetic Field by Polarization Observations of Supernova Remnants.- Radio Polarimetry of Tycho's SNR.- The Magnetic Field of the Crab as Revealed by New, High Resolution, Multi-Band Radio Images.- Magnetic Fields in Young SNRs.- 4. Magnetohydrodynamics of Galactic Magnetic Fields.- Dynamo in Astrophysics.- Large-Scale Galactic arid Intergalactic Magnetic Fields.- Torus-Dynamo.- Key Problems of Flat Objects Dynamo Theory and Ways of Their Solution.- Mean-Field Models of Galactic Dynamos Admitting Axisymmetric and Non-Axisymmetric Magnetic Field Structures.- The Alpha-Effect in Galaxies is Highly Anisotropic.- Galactic Dynamos Without Sharp Boundaries: Non-Axisymmetric Fields in Axisymmetric Disks?.- Dynamo Generation of Galactic Magnetic Fields.- Galactic Dynamo Theory Confronted with Observations.- Bisymmetric Spiral Magnetic Fields and Gravitational Instabilities of Galactic Disks.- Enhancement of Galactic Dynamos by Density Waves.- Swing Excitation of Galactic Magnetic Fields Induced by Spiral Density Waves.- 3-D Models of Galaxy Magnetic Fields with Spiral Shocks.- Galactic Dynamos and Density Wave Theory.- Phenomena Involving Magnetic Vortex Tubes.- Magnetic Viscosity as the Dominant Shear Force in Accretion Disks.- 3-Dimensional Particle-in-Cell Simulations of Spiral Galaxies.- Magnetohydrodynamic Simulation of the Evolution of Large-Scale Magnetic Fields in Disk Galaxies.- On the Nature of Magnetohydrodynamic Turbulence in the Interstellar Medium.- Regular and Stochastic Dynamics of Relativistic Particles in Alfvén Waves.- Magnetic Field in a Turbulent Galactic Disk.- The Propagation of Discontinuities in Gas Flows in the ISM and its Relation to the Galactic Synchrotron Radio Emission.- Turbulent Mixing in Circumstellar Space in the Presence of Magnetic Fields.- Diamagnetic Cavities in the Interstellar Medium.- Spontaneous Discontinuities in Galactic Magnetic Fields and the Creation of Galactic X-ray Halos.- Interstellar Magnetohydrodynamic Waves as Revealed by Radio Astronomy.- Galactic Winds and Magnetic Fields from Spiral Galaxies.- Galactic Winds: The Role of Cosmic Rays.- Interaction of Cosmic Rays with a Galactic Corona Bow-Shock.- The Role of Cosmic Rays and Alfvén Waves in the Structure of the Galactic Halo.- 5. The Polarization, Magnetic Field and Velocity Structure of External Spiral Galaxies.- Multi-Frequency Radio Observations of Spiral Galaxies and Their Interpretation.- Modelling Faraday Rotation in Galaxies.- The Detailed Magnetic Field Structure in the SW Quadrant of M31.- What Mechanism Depolarizes the Emission from the SW Arm of M31?.- CO Observations of a Region with Strong Polarization in M31.- Polarization in the Magellanic Clouds.- The Magnetic Field in M33.- Polarized Radio Emission from M51.- Polarized Radio Emission from NGC 6946.- Linearly Polarised Radio Emission from M83 (NGC 5236) and NGC 891.- The Magnetic Field in Edge-on Galaxies.- Optical and Radio Surface Photometry of NGC 891.- Radio Polarization Studies of Some Southern Galaxies.- Vertical Magnetic Fields in Spiral Galaxies.- Magnetic Fields and Star Formation for the ANS Sample of Galaxies.- Equipartition: Fact or Fiction?.- Modelling the 60?m/20cm Infrared-to-Radio Ratio Within Spiral Galaxies.- Constraints on the Magnetic Fields in Galaxies Implied by the Infrared-to-Radio Correlation.- Magnetic Field Strengths of Galaxies and the Far-Infrared/Radio Correlation.- Dust Grain Orientation in the Interstellar Magnetic Field.- Optical Polarisation Studies of Galaxies.- A CCD Polarimeter with Focal Reducer.- Optical Polarization of M82.- Magnetic Field Structure in the Small Magellanic Cloud.- Stochastic Star Formation and Magnetic Fields.- 6. Magnetic Fields in Molecular Clouds, Dark Globules and in the Pre-Stellar and Circumstellar Environment.- The Role of Magnetic Fields in Star Forming Regions.- The Magnetic Field in Highly Dense Molecular Clouds.- Molecular Cloud Cores and Protostars: Offsprings of Gravity and Cosmic Magnetism.- Magnetic Flux Loss from Interstellar Clouds with Various Grain Size Distributions.- The Rate of Angular Momentum Loss from Cloud Cores.- Magnetic Braking of Interstellar Clouds.- Magnetic Field and Ambipolar Diffusion in Molecular Clouds and Protostars.- Magnetic Fields in Molecular Cloud Cores.- Observational Aspects of Magnetic Fields in Molecular Clouds.- Magnetic Fields in Interstellar Masers.- Observability of the Magnetic Field in Molecular Clouds.- Magnetic Fields in Dark Cloud Cores and H2O Masers.- Observations and Models of Magnetic Molecular Clouds.- Magnetically Controlled Gravitational Instabilities in the Taurus Molecular Complex.- VLA Mapping of Magnetic Fields in W3 and S106.- The H? Emission of the PMS Star Serpens/SVS2.- The Magnetic Field in the Perseus Molecular Cloud Complex.- Magnetic Fields in Molecular Clouds at High Galactic Latitudes.- Polarization Measurements of Some Herbig Ae/Be Stars.- Magnetic Fields and Star Formation: Imaging Polarimetry of Two Reflection Nebulae.- Near Infrared Polarimetry of Dark Clouds and Star Forming Regions - Two Micron Polarization Survey of T Tauri Stars.- Detection of Synchrotron Emission from a Unique Herbig Haro Object in Orion.- Alignment of Circumstellar H-H Flows by the Interstellar Magnetic Field.- Jet Interactions with Molecular Clouds: C-Shock Models.- Topological Solutions for Collimated MHD Flows.- Magnetically Driven Jets.- MHD Reconnection Model for Optical Jets, H-H Objects and GGD Objects.- Numerical Models of Magnetic Disk Accretion in Star Forming Regions.- Chemical Diagnostics of Turbulent Magnetic Boundary Layers.- MHD Simulations of Mass Outflows from Star Forming Regions.- The Collimation of MHD Winds: Bipolar Flows and Jets.- Resistive Instabilities in a Two-Dimensional MHD Turbulent Flow.- Cosmic Ray Acceleration and ? Ray Induced by the Interaction of the Ejecta of SN1987A with the Magnetized Cloud.- 7. Magnetic Fields in Galactic Nuclei.- The Magnetic Field in the Inner 70 Parsecs of the Milky Way.- The Large-Scale Magnetic Field Structure near the Galactic Center.- Magnetic Filaments in the Negative-Latitude Extension of the Radio Arc Near the Galactic Center.- A Wide Field ?90 cm Image Around the Galactic Center - Evidence for a Poloidal Magnetic Field.- Random Precessing Jet and Accretion Disk at the Galactic Center.- MHD Models of Galactic Center Lobes, Shells, and Filaments.- Interaction between Magnetic Fields and Molecular Clouds on the Radio Arc.- OH Zeeman Determination of the Magnetic Field at the Galactic Center.- Zeeman Observations of the Magnetic Field in the Galactic Center.- Polarization Properties of Radio Cores.- Poloidal Magnetic Fields in Galactic Central Regions.- Dynamo Driven Mean Magnetic Field in Accretion Disks of Compact Astrophysical Objects and Its Manifestations.- Synchrotron Radiation from Energetic Electrons Emitted by AGN: A Probe for Magnetic Fields in External Galaxies.- Magnetic Fields in Radio-Quiet Quasars.- Stability of Luminous Discharges in Strong Fields.- 8. The Role of Magnetic Fields in Radio Source Jets and Extended Radio Lobes.- An Overview of Computational MHD Jets and their Comparisons with Recent High Resolution Radio Images.- Magnetic Production of Extragalactic Jets.- Computational MHD Jets.- Gravo-Magnetodynamic Engine for Cosmic Jets.- Radiogaps: Stability of Electron/Positron Jets in Large-Scale Magnetic Fields.- Shock Conditions in Magnetized Jets.- High Energy Physics in Magnetic Jets and Hot Spots.- Numerical Observations of a Restarting Radio Jet.- Oblique Shocks in Extragalactic Jets.- The Shock Structure in Current-Carrying Jets.- The Combined Effects of Magnetic Fields and Rotation on the Acceleration of Jets: A Quasi-One-Dimensional MHD Model.- A Theoretical MHD Model for Extragalactic Jets and its Comparison with the Observations.- Origin of Magnetic Fields in Jets and Radio Galaxies.- Importance of Magnetic Effects in a Two-Flow Model for Extragalactic Radio Jets.- Contour Simulations of Astrophysical Jets.- Collimated Bipolar Outflow and the Formation of Nuclear Spirals; Possible Role of Magnetic Fields.- Comparison of Radio and Optical Polarization in Extended Extragalactic Radio Sources I. Observations.- Comparison of Radio and Optical Polarization in Extended Extragalactic Radio Sources II. Implications for the Magnetic Fields.- Peculiar Magnetic Field Structures in 4C49.22 (1150+497).- Polarization Observations of Selected Radio Galaxies at 327 MHz.- Filaments Evolution in Extended Radio Sources.- 9. Magnetic Fields in the Galactic Environment, Galaxy Clusters and Intergalactic Medium.- Magnetic Fields and Ionized Gas in Elliptical Galaxy Halos.- Magnetic Fields in Cooling Flow Clusters.- The Polarization Structure of Centaurus A.- Search for Extragalactic Radio Sources with Large Rotation Measure.- Asymmetric Depolarization in Double Radio Sources.- The Production of Rotation Measure Gradients in the Lobes of Extragalactic Radio Sources.- Properties of the Medium Causing Asymmetric Depolarization in Strong Double Radio Sources with one Jet.- The Strength and Structure of the Intracluster Magnetic Field in the Coma Cluster of Galaxies.- High Frequency Observations of a Large Faraday Rotation Galaxy in a Cluster.- Intracluster Magnetic Fields from X-ray and Radio Measurements.- Evidence of a Large Scale Magnetic Field in the Coma-A1367 Supercluster.- Magnetic Fields of Radio Galaxies in Abell Clusters 115 and 568.- The Role of Extragalactic Jets in the Magnetization of the Intergaiactic Medium.- Intermittent Magnetic Fields Generated by Turbulence in Galaxies and Galaxy Clusters.- Intergaiactic Magnetic Fields and the Morphology of Spiral Galaxies.- 10. Magnetic Fields at High Redshifts and in the Early Universe.- Cosmic Magnetic Fields and Superconducting Strings.- Quasar Rotation Measures and Optical Absorption Spectra - What can we Learn about Cosmic Magnetic Fields?.- Non-Conventional Origin of Large-Scale Magnetic Fields.- Magnetic Field Generation in Protogalactic Halos.- The Present State of a Primordial Galactic Field.- On the Origin of Cosmic Magnetic Fields.- 11. Concluding Summary Remarks.- Concluding Summary Remarks.- Author Index.