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Magnetic Fields in Disks and Halos of Spiral Galaxies

Published online by Cambridge University Press:  03 August 2017

Rainer Beck
Rainer Beck*
Affiliation:
Max-Planck-Institut für Radioastronomie Auf dem Hügel 69 D-5300 Bonn 1 Germany

Abstract

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Spiral galaxies host interstellar magnetic fields of 4-15 μG total strength. A significant fraction of the field lines shows large-scale structures. At face-on or moderately inclined view, the field lines run generally parallel to the spiral arms, either with uniform direction with respect to azimuthal angle (axisymmetric spiral, ASS), with one reversal along azimuthal angle (bisymmetric spiral, BSS), or with spiral orientation without dominating direction.

At edge-on view, the field is concentrated in a thin disk, often surrounded by a thick radio disk with field lines mostly parallel to the plane, similar to the quadrupole-type dynamo field. Radio polarization data from NGC891 indicate that the thermal gas seen in Hα is responsible for Faraday depolarization. The required scaleheight of the field of ~4 kpc is comparable to the value expected in case of energy equipartition between magnetic fields and cosmic rays. The interacting edge-on galaxy NGC 4631 shows a much larger radio halo with field lines perpendicular to the disk, possibly driven by a strong galactic wind or the result of a dipole-type halo field.

Field lines bending out of the plane are also visible in face-on galaxies as regions with high rotation measures and low star-formation activity. The resemblance to the phenomenon of the solar corona suggests to call them “galactic coronal holes”.

Type
II. The Disk-Halo Interface in Other Galaxies
Information
Symposium - International Astronomical Union , Volume 144: The Interstellar Disk-Halo Connection in Galaxies , 1991 , pp. 267 - 280
Copyright
Copyright © Kluwer 1991 

References

REFERENCES

Allen, R.J., Sukumar, S. (1990) Ap. J. (in press) Google Scholar
Bash, F., Hausman, M., Papaloizou, J. (1981) Ap. J. 245, 92 Google Scholar
Beck, R. (1982) Astr. Ap. 106, 121 Google Scholar
Beck, R. (1986) IEEE Trans. on Plasma Science PS-14, 740 Google Scholar
Beck, R., Golla, G. (1988) Astr. Ap. 191, L9 Google Scholar
Beck, R., Loiseau, N., Hummel, E., Berkhuijsen, E.M., Gräve, R., Wielebinski, R. (1989) Astr. Ap. 222, 58 Google Scholar
Beck, R., Buczilowski, U.R., Harnett, J.I. (1990) in Galactic and Intergalactic Magnetic Fields , eds. Beck, R., Kronberg, P.P., Wielebinski, R., Kluwer, Dordrecht, p. 213 Google Scholar
Beck, R., Berkhuijsen, E.M., Bajaja, E. (1991) in Dynamics of Galaxies and Molecular Cloud Distribution , IAU Symp. No. 146, eds. Combes, F., Casoli, F., Kluwer, Dordrecht Google Scholar
Bicay, M.D., Helou, G., Condon, J.J. (1989) Ap. J. 338, L53 Google Scholar
Bonnarel, F., Boulesteix, J., Marcelin, M. (1986) Astr. Ap. Suppl. 66, 149 Google Scholar
Brandenburg, A., Tuominen, I., Krause, F. (1990) Geophys. Astrophys. Fluid Dynamics 50, 95 Google Scholar
Breitschwerdt, R., McKenzie, J.F., Völk, H.J. (1990) Astr. Ap. (in press) Google Scholar
Brett, L., Kahn, F. (1990) in The Interstellar Disk-Halo Connection in Galaxies , Poster Proc. IAU Symp. No. 144, ed. Bloemen, H., Leiden Observatory, p. 81 Google Scholar
Buczilowski, U.R., Beck, R. (1990) Astr. Ap. (in press) Google Scholar
Chi, X., Wolfendale, A.W. (1990) M.N.R.A.S. 245, 101 Google Scholar
Chiba, M., Tosa, M. (1989) M.N.R.A.S. 238, 621 Google Scholar
Chiba, M., Tosa, M. (1990) in Galactic and Intergalactic Magnetic Fields , eds. Beck, R., Kronberg, P.P., Wielebinski, R., Kluwer, Dordrecht, p. 131 CrossRefGoogle Scholar
Clifford, P., Elmegreen, B.G. (1983) M.N.R.A.S. 202, 629 CrossRefGoogle Scholar
Dahlem, M. (1990) Ph.D. thesis, University of Bonn Google Scholar
Dame, T., Thaddeus, P., Koper, E. (1991), in Dynamics of Galaxies and Molecular Cloud Distribution , IAU Symp. No. 146, eds. Combes, F., Casoli, F., Kluwer, Dordrecht Google Scholar
Dettmar, R.-J. (1990) Astr. Ap. 232, L15 Google Scholar
Donner, K.J., Brandenburg, A. (1990) Astr. Ap. (in press) Google Scholar
Golla, G., Beck, R. (1990) in The Interstellar Disk-Halo Connection in Galaxies , Poster Proc. IAU Symp. No. 144, ed. Bloemen, H., Leiden Observatory, p. 47 Google Scholar
Harnett, J.I., Haynes, R.F., Klein, U., Wielebinski, R. (1989) Astr. Ap. 216, 39 Google Scholar
Helou, G., Bicay, M.D. (1990), in Galactic and Intergalactic Magnetic Fields , eds. Beck, R., Kronberg, P.P., Wielebinski, R., Kluwer, Dordrecht, p. 239 CrossRefGoogle Scholar
Horellou, C. (1990) Diplomarbeit, University of Bonn Google Scholar
Hummel, E. (1990) in Windows on Galaxies , eds. Fabbiano, G. et al., Kluwer, Dordrecht, p. 141 Google Scholar
Hummel, E., Lesch, H., Wielebinski, R., Schlickeiser, R. (1988a) Astr. Ap. 197, L29 Google Scholar
Hummel, E., Davies, R.D., Wolstencroft, R.D., van der Hulst, J.M., Pedlar, A. (1988b) Astr. Ap. 199, 91 Google Scholar
Hummel, E., Beck, R., Dahlem, M. (1990a) Astr. Ap. (in press) Google Scholar
Hummel, E., Dahlem, M., van der Hulst, J.M., Sukumar, S. (1990b) Astr. Ap. (in press) Google Scholar
Hummel, E., Beck, R., Dettmar, R.-J. (1990c) Astr. Ap. (in press) Google Scholar
Klein, U., Urbanik, M., Beck, R., Wielebinski, R. (1983) Astr. Ap. 127, 177 Google Scholar
Ko, C.M., Parker, E.N. (1989) Ap. J. 341, 828 CrossRefGoogle Scholar
Krause, F., Meinel, R., Elstner, D., Rüdiger, G. (1990) in Galactic and Intergalactic Magnetic Fields , eds. Beck, R., Kronberg, P.P., Wielebinski, R., Kluwer, Dordrecht, p. 97 Google Scholar
Krause, M. (1990) in Galactic and Intergalactic Magnetic Fields , eds. Beck, R., Kronberg, P.P., Wielebinski, R., Kluwer, Dordrecht, p. 187 Google Scholar
Krause, M., Hummel, E., Beck, R. (1989a) Astr. Ap. 217, 4 Google Scholar
Krause, M., Beck, R., Hummel, E. (1989b) Astr. Ap. 217, 17 Google Scholar
Kulsrud, R. (1986) in Plasma Astrophysics , ESA SP-251, p. 531 Google Scholar
Lesch, H., Crusius, A., Schlickeiser, R., Wielebinski, R. (1989) Astr. Ap. 217, 99 Google Scholar
Michel, F.C., Yahil, A. (1973) Ap. J. 179, 771 CrossRefGoogle Scholar
Molchanov, S., Ruzmaikin, A., Sokolov, D. (1985) Sov. Phys. Usp. 28, 307 Google Scholar
Moss, D., Tuominen, I. (1990) Geophys. Astrophys. Fluid Dynamics 50, 113 Google Scholar
Mouschovias, T. Ch. (1990) in Galactic and Intergalactic Magnetic Fields , eds. Beck, R., Kronberg, P.P., Wielebinski, R., Kluwer, Dordrecht, p. 269 Google Scholar
Neininger, N., Beck, R., Backes, F. (1990) in Galactic and Intergalactic Magnetic Fields , eds. Beck, R., Kronberg, P.P., Wielebinski, R., Kluwer, Dordrecht, p. 253 Google Scholar
Norman, C.A., Ikeuchi, S. (1989) Ap. J. 345, 372 CrossRefGoogle Scholar
Parker, E.N. (1990) in Galactic and Intergalactic Magnetic Fields , eds. Beck, R., Kronberg, P.P., Wielebinski, R., Kluwer, Dordrecht, p. 1 Google Scholar
Rand, R.J., Kulkarni, S.R., Hester, J.J. (1990) Ap. J. 352, L1 Google Scholar
Ruzmaikin, A. (1990) in Galactic and Intergalactic Magnetic Fields , eds. Beck, R., Kronberg, P.P., Wielebinski, R., Kluwer, Dordrecht, p. 83 Google Scholar
Ruzmaikin, A., Sokoloff, D., Shukurov, A. (1988) Nature 336, 341 CrossRefGoogle Scholar
Ruzmaikin, A., Sokoloff, D., Shukurov, A., Beck, R. (1990) Astr. Ap. 230, 284 Google Scholar
Sawa, T., Fujimoto, M. (1986) P.A.S. Japan 38, 133 Google Scholar
Scarrott, S.M., Rolph, C.D., Semple, D.P. (1990) in Galactic and Intergalactic Magnetic Fields , eds. Beck, R., Kronberg, P.P., Wielebinski, R., Kluwer, Dordrecht, p. 245 Google Scholar
Sofue, Y. (1987) P.A.S. Japan 39, 547 Google Scholar
Sofue, Y. (1990) in Galactic and Intergalactic Magnetic Fields , eds. Beck, R., Kronberg, P.P., Wielebinski, R., Kluwer, Dordrecht, p. 227 Google Scholar
Sofue, Y., Beck, R. (1987) P.A.S. Japan 39, 541 Google Scholar
Sukumar, S., Allen, R.J. (1989) Nature 340, 537 CrossRefGoogle Scholar
Sukumar, S., Klein, U., Gräve, R. (1987) Astr. Ap. 184, 71 Google Scholar
Urbanik, M. (1990) in The Interstellar Disk-Halo Connection in Galaxies , Poster Proc. IAU Symp. No. 144, ed. Bloemen, H., Leiden Observatory, p. 111 Google Scholar
Vallée, J.P. (1988) A. J. 95, 750 Google Scholar
Vallée, J.P. (1990) Ap. J. (in press) Google Scholar
Völk, H.J. (1989) Astr. Ap. 218, 67 Google Scholar
Wielebinski, R. (1990) in The Interstellar Medium in Galaxies , eds. Thronson, H.A., Shull, J.M., Kluwer, Dordrecht, p. 349 Google Scholar
Wunderlich, E., Klein, U., Wielebinski, R. (1987) Astr. Ap. Suppl. 69, 487 Google Scholar