Interstellar Magnetic Fields: Observation and Theory

285 Pages·1987·24.852 MB·English

by  R. Beck (auth.), Dr. Rainer Beck, Dr. Roland Gräve (eds.)

Interstellar Magnetic Fields
Interstellar
Magnetic Fields
Observation and Theory
Proceedings of a Workshop,
Held at SchloB Ringberg, Tegernsee,
September 8-12, 1986
Editors: R. Beck and R. Grave
With 125 Figures
Springer-Verlag Berlin Heidelberg New York
London Paris Tokyo
Dr. Rainer Beck
Dr. Roland Grave
Max-Planck-Institut fOr Radioastronomie, Auf dem Hugel 69,
D-5300 Bonn 1, Fed. Rep. of Germany
ISBN-13:978-3-642-72623-1 e-ISBN-13:978-3-642-72621-7
001: 10.1007/978-3-642-72621-7
This work is subject to copyright. All rights are reserved, whether the whole or part of the material is
concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broad
casting, reproduction on microfilms or in other ways, and storage in data banks. Duplication of this
publication or parts thereof is only permitted under the provisions of the German Copyright Law of
September 9, 1965, in its version of June 24, 1985, and a copyright fee must always be paid. Violations
fall under the prosecution act of the German Copyright Law.
©Springer-Verlag Berlin Heidelberg 1987
Softcover reprint of the hardcover 1st edition 1987
The use of registered names, trademarks, etc. in this publication does not imply, even in the absence of
a specific statement, that such names are exempt from the relevant protective laws and regulations and
therefore free for general use.
2153/3150-543210
Preface
The subject of interstellar magnetic fields is of increasing interest to both
observational and theoretical astronomers. Consequently, it was opportune
for both groups to convene and discuss the current state of research and future
prospects. For this purpose, the Max-Planck-Gesellschaft zur Forderung der
Wissenschaften e.V. generously provided its unique conference centre SchloB
Ringberg.
The scientific organising committee consisted of Profs. W. Hillebrandt
(Max-Planck-Institut fUr Physik und Astrophysik, Munchen) and
R. Wielebinski (Max-Planck-Institut fUr Radioastronomie, Bonn). The lo
cal organising committee comprised Gabriele Breuer (conference secretary)
and the Editors. '
These proceedings summarise the lectures and short contributions pre
sented at the workshop. Although extremely productive, the discussions could
not, unfortunately, be included.
We thank the staff of the castle, and especially its administrator, Mr.
Hormann, for providing the excellent environment conducive to smooth run
ning of the conference. We acknowledge the Max-Planck-Gesellschaft for its
support in financing the workshop. Thanks are also due to all participants
for their enthusiasm and (generally!) prompt submission of manuscripts. Last
but not least, we thank Gabriele Breuer for her invaluable help before, dur
ing and after the days at SchloB Ringberg. She skillfully typed and retyped
many of the manuscripts for these proceedings and unstintingly performed
last minute corrections.
We hope that some of the ideas presented here will stimulate further
discussion and research in this area.
Bonn, December 1986 R.Beck
R. Grave
v

R. M.
Furst, E. Buczilowski, U .Reif, K. Krause, M. Tosa, M. Volk, H. Junkes, N. Hummel, E. Breuer, G. Reich, W. Browne, P.F. Schmidt-Voigt, Kossl, D. Sieber, W.
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Summary of Part I
VIII
Contents
Part I Large-Scale Magnetic Fields in Galaxies
Interstellar Magnetic Fields - Past, Present and Future
By R. Beck (With 3 Figures) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Dynamo Excitation in Very Large Scales
By F. Krause (With 4 Figures) ........................... 8
Magnetic Fields of Galaxies. By A. Ruzmaikin (With 5 Figures) 16
Bisymmetric Spiral Magnetic Fields in Spiral Galaxies
By M. Fujimoto (With 6 Figures) ......................... 23
Global Structure of Magnetic Fields in Spiral Galaxies
By Y. Sofue (With 3 Figures) ............................ 30
Rotation Measures and Depolarization near the Minor Axis in M31.
By E.M. Berkhuijsen, R. Beck, and R. Grave (With 4 Figures) 38
High Resolution Polarization Observations of M31
By N. Loiseau, E. Hummel, R. Beck, and R. Wielebinski
(With 2 Figures) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
The Magnetic Field in IC 342
By R. Grave and R. Beck (With 4 Figures) .................. 47
High Resolution Observations of Linearly Polarized Emissions of
IC 342. By M. Krause, E. Hummel, and R. Beck (With 1 Figure) 52
Magnetic Fields in M33 and NGC 6946
By U.R. Buczilowski (With 1 Figure) ................... . . . . 54
The Magnetic Field Structure in M81
By M. Krause, R. Beck, and E. Hummel (With 1 Figure) 57
The Magnetic Field in the Anomalous Arms in NGC 4258
By E. Hummel, M. Krause, and R. Beck (With 1 Figure) 61
Spiral Arms as Ejection Phenomena
By H. Arp (With 4 Figures) ............................. 65
IX
Optical Polarisation Studies of Galaxies. By S.M. Scarrott,
D.W. Ward-Thompson, and R.F. Warren-Smith (With 3 Figures) 71
Nonthermal Radio Emission from Dwarf Galaxies: Do They Host
Large-Scale Magnetic Fields?
By U. Klein and R. Grave (With 2 Figures) .................. 76
Scale Properties of the Turbulent Magnetic Field in the
Large Magellanic Cloud. By J. Spieker and J. V. Feitzinger
(With 2 Figures) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
Magnetic Fields and Faraday-Active Clouds out to the Distances of
Quasars. By P.P. Kronberg (With 6 Figures) ................. 86
Part II Large-Scale Magnetic Fields in Our Galaxy
Magnetic Fields in the Galaxy. By R. Wielebinski 96
Interstellar Polarization and Magnetic Fields
By P. Cugnon (With 1 Figure) ........................... 100
The Local Magnetic Field as Determined by Pulsar Rotation
Measures. By W. Sieber (With 3 Figures) ................... 110
Extended Polarized Emission at 2695 MHz in the Galactic Plane
By N. Junkes, E. Furst, and W. Reich (With 2 Figures) ......... 115
The Radio Continuum Brightness Minimum near Polaris: A Hole in
the Interstellar Magnetic Field? By K. Reif (With 4 Figures) ..... 119
Vertical Expansion of the Galactic Gas Disk Behind the Spiral Shock
Waves. By M. Tosa (With 2 Figures) .. . . . . . . . . . . . . . . . . . . . .. 123
Magnetic Field Effects in Galactic Disks
By M.L. Sanchez-Saavedra and E. Battaner (With 2 Figures) ..... 128
Magnetic Field Structure of the Galaxy and the Formation of Galactic
Winds
By D. Breitschwerdt, J.F. McKenzie, and H.J. Volk (With 5 Figures) 131
Galaxy Magnetic Fields and Hidden Matter in Galaxies
By A.H. Nelson (With 2 Figures) ......................... , 142
Observations of Linear Polarization in the Galactic Centre Region
By W. Reich, Y. Sofue, M. Inoue, and J.H. Seiradakis
(With 3 Figures) ...... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 146
The Magnetic Field in the Galactic Center Region
By Y. Sofue and W. Reich (With 2 Figures) .. . . . . . . . . . . . . . . .. 150
x
Part III Magnetic Fields in Star-Forming Regions and Supernova
Remnants
The Strength of the Interstellar Magnetic Fields and Its Possible Role
in HI Cloud Dynamics. By G.L. Verschuur (With 4 Figures) 154
Optical Polarisation Studies of Star Formation Regions
By S.M. Scarrott, T .M. Gledhill, and R.F. Warren-Smith
(With 2 Figures) .......................... . . . . . . . . . . .. 161
Observation of Magnetic Field Structure Around Newly Formed Stars
By R.F. Warren-Smith, P.W. Draper, and S.M. Scarrott
(With 2 Figures) ............................ . . . . . . . . . . 166
Stochastic Star Formation, Magnetic Fields and the Fine Structure of
Spiral Arms. By J.V. Feitzinger and J. Spicker (With 5 Figures) 171
Magnetic Fields in Supernova Remnants - Results from Radio
Continuum Observations. By E. Fiirst (With 3 Figures) ......... 179
Magnetic Fields in Supernovae and Supernova Shells
By W. Kundt (With 3 Figures) ........................... 185
Part IV Magnetic Fields in Accretion Disks and Jets
Magnetic Fields, Black Holes and Accretion Disks
By E. Asseo (With 5 Figures) ............................ 194
The Influence of External Magnetic Fields on the Structure of Thin
Accretion Disks
By U. Anzer, G. Borner, and E. Meyer-Hofmeister (With 2 Figures) 203
Stellar and Extragalactic Jets: An Introduction. By W. Hillebrandt 208
Magnetic Vortex Tubes and Charge Acceleration. By P.F. Browne 211
Collimation of Supersonic Gas Flows by Toroidal Magnetic Fields
By D. Kossl (With 4 Figures) ............................ 222
Jet Formation in Rapidly Rotating Magnetospheres
By M. Camenzind (With 4 Figures) ........................ 229
Part V Theoretical Aspects Related to Cosmical Magnetic Fields
Evolving Magnetostatic Equilibria. By J.J. Aly ............... 240
Avoiding Magnetic Monopoles in Numerical MHD Calculations
By M. Schmidt-Voigt (With 3 Figures) ..................... 251
Stochastic Particle Acceleration at Magnetohydrodynamic Shock
Waves. By W. Droge (With 2 Figures) ..................... 255
XI