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Galactic and Extragalactic Magnetic Fields

  • Conference paper
The Astrophysics of Galactic Cosmic Rays

Part of the book series: Space Sciences Series of ISSI ((SSSI,volume 13))

Abstract

The current state of research of the Galactic magnetic field is reviewed critically. The average strength of the total field derived from radio synchrotron data, under the energy equipartition assumption, is 6±2 μG locally and about 10±3 μG at 3 kpc Galactic radius. These values agree well with the estimates using the locally measured cosmic-ray energy spectrum and the radial variation of protons derived from γ-rays. Optical and synchrotron polarization data yield a strength of the local regular field of 4 ± 1 μG, but this value is an upper limit if the field strength fluctuates within the beam or if anisotropic fields are present. Pulsar rotation measures, on the other hand, give only 1.4 ± 0.2 μG, a lower limit if fluctuations in regular field strength and thermal electron density are anticorrelated along the pathlength. The local regular field may be part of a ‘magnetic arm’ between the optical arms. However, the global structure of the regular Galactic field is not yet known. Several large-scale field reversals in the Galaxy were detected from rotation measure data, but a similar phenomenon was not observed in external galaxies. The Galactic field may be young in terms of dynamo action so that reversals from the chaotic seed field are preserved, or a mixture of dynamo modes causes the reversals, or the reversals are signatures of large-scale anisotropic field loops. The Galaxy is surrounded by a thick disk of radio continuum emission of similar extent as in edge-on spiral galaxies. While the local field in the thin disk is of even symmetry with respect to the plane (quadrupole), the global thick-disk field may be of dipole type. The Galactic center region hosts highly regular fields of up to milligauss strength which are oriented perpendicular to the plane. A major extension of the data base of pulsar rotation measures and Zeeman splitting measurements is required to determine the structure of the Galactic field. Further polarization surveys of the Galactic plane at wavelengths of 6 cm or shorter may directly reveal the fine structure of the local magnetic field.

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References

  • Andreasyan, R. R. and Makarov, A. N.: 1988, ‘Model of Two-component Magnetic Field of the Galaxy’, Astrophysics 28, 247–253.

    Article  ADS  Google Scholar 

  • Beck, R.: 2000, ‘Magnetic Fields in Normal Galaxies’, Phil. Trans. R. Soc. London A358, 777–796. Beck, R. and Hoernes, P.: 1996, ‘Magnetic Spiral Arms in the Galaxy NGC 6946’, Nature 379, 4749.

    Google Scholar 

  • Beck, R., Loiseau, N., Hummel, E., Berkhuijsen, E. M., Gräve, R., and Wielebinski, R.: 1989, ‘High-resolution Polarization Observations of M31 I. Structure of the Magnetic Field in the Southwestern Arm’, Astron. Astrophys. 222, 58–68.

    ADS  Google Scholar 

  • Beck, R., Brandenburg, A., Moss, D., Shukurov, A., and Sokoloff, D.: 1996, ‘Galactic Magnetism: Recent Developments and Perspectives’, Ann. Rev. Astron. Astrophys. 34, 155–206.

    Article  ADS  Google Scholar 

  • Beck, R., Berkhuijsen, E. M., and Uyaniker, B.: 1999, in M. Ostrowski and R. Schlickeiser (eds.), ‘Studies of Turbulent Interstellar Magnetic Fields Using Radio Emission’, Plasma Turbulence and Energetic Particles in Astrophysics, Obserwatorium Astronomiczne, Krakow, 1999, pp. 517.

    Google Scholar 

  • Berkhuijsen, E. M.: 1971, ‘A Survey of the Continuum Radiation at 820 MHz between Declinations —7° and +85°’, Astron. Astrophys. 14, 359–386.

    ADS  Google Scholar 

  • Berkhuijsen, E. M., Horellou, C., Krause, M., Neininger, N., Poezd, A. D., Shukurov, A., and Sokoloff, D. D.: 1997, ‘Magnetic Fields in the Disk and Halo of M51’, Astron. Astrophys. 318, 700–720.

    ADS  Google Scholar 

  • Beuermann, K., Kanbach, G., and Berkhuijsen, E. M.: 1985, ‘Radio Structure of the Galaxy: Thick Disk and Thin Disk at 408 MHz’, Astron. Astrophys. 153, 17–34.

    ADS  Google Scholar 

  • Brogan, C. L., Frail, D. A., Goss, W. M., and Troland, T.H.: 2000, ‘OH Zeeman Magnetic Field Detections Toward Five Supernova Remnants Using the VLA’, Astrophys. J. 537, 875–890.

    Article  ADS  Google Scholar 

  • Brouw, W. N. and Spoelstra, T. A. Th.: 1976, ‘Linear Polarization of the Galactic Background at Frequencies Between 408 and 1411 MHz. Reductions’, Astron. Astrophys. Suppl. 26, 129–146.

    ADS  Google Scholar 

  • Bykov, A., Popov, V., Skukurov, A., and Sokoloff, D.: 1997, ‘Anomalous Persistence of Bisymmetric Magnetic Structures in Spiral Galaxies’, Monthly Notices Roy. Astron. Soc. 292, 1–10.

    ADS  Google Scholar 

  • Dumke, M. and Krause, M.: 1998, in D. Breitschwerdt, M. J. Freyberg, and J. Trümper (eds.), ‘Radio and Polarization Properties in the Disk and Halo of Edge-on Spirals’, The Local Bubble and Beyond, Springer-Verlag, Berlin, pp. 555–558.

    Google Scholar 

  • Dumke, M., Krause, M., Wielebinski, R., and Klein, U.: 1995, ‘Polarized Radio Emission at 2.8 cm from a Selected Sample of Edge-on Galaxies’, Astron. Astrophys. 302, 691–703.

    ADS  Google Scholar 

  • Duncan, A. R., Haynes, R. F., Jones, K. L., and Stewart, R. T.: 1997, ‘Polarized Radio Emission Over the Southern Galactic Plane at 2.4 GHz’, Monthly Notices Roy. Astron. Soc. 291, 279–295.

    Article  ADS  Google Scholar 

  • Duncan, A. R., Reich, P., Reich, W., and Fürst, E.: 1999, ‘Polarimetric Structure in the First Galactic Quadrant from the 2.695 GHz Effelsberg Survey’, Astron. Astrophys. 350, 447–456.

    ADS  Google Scholar 

  • Ferguson, A. M. N., Wyse, R. F. G., Gallagher, J. S., and Hunter, D. A.: 1998, ‘Discovery of Recent Star Formation in the Extreme Outer Regions of Disk Galaxies’, Astrophys. J. 506, L19–L22.

    Article  ADS  Google Scholar 

  • Fletcher, A., Beck, R., Berkhuijsen, E. M., and Shukurov, A.: 2000, in E. M. Berkhuijsen, R. Beck, and R. A. M. Walterbos (eds.), ‘The Regular Magnetic Fields in M31 and M33 From Polarization Observations’, The Interstellar Medium in M31 and M33,Shaker-Verlag, pp. 203–206.

    Google Scholar 

  • Frick, P., Stepanov, R., Shukurov, A., and Sokoloff, D.: 2001, ‘Structures on the RM Sky’, Monthly Notices Roy. Astron. Soc. 325, 649–664.

    Article  ADS  Google Scholar 

  • Greaves, J. S., Holland, W. S., Jenness, T., and Hawarden, T. G.: 2000, ‘Magnetic Field Surrounding the Starburst Nucleus of the Galaxy M82 from Polarized Dust Emission’, Nature 404, 732–733.

    Article  ADS  Google Scholar 

  • Han, J. L. and Qiao, G. J.: 1994, ‘The Magnetic Field in the Disk of Our Galaxy’, Astron. Astrophys. 288, 759–772.

    ADS  Google Scholar 

  • Han, J. L. and Qiao, G. J.: 1996, in S. Johnston, M. A. Walker, and M. Bailes (eds.), ‘On Galactic Magnetic Field Derived from RMs of Pulsars’, Pulsars: Problems and Progress, ASP Conf. Ser. 105, 485–486.

    Google Scholar 

  • Han, J. L., Manchester, R. N., Berkhuijsen, E. M., and Beck, R.: 1997, ‘Antisymmetric Rotation Measures in Our Galaxy: Evidence for an AO Dynamo’, Astron. Astrophys. 322, 98–102.

    ADS  Google Scholar 

  • Han, J. L., Manchester, R. N., and Qiao, G. J.: 1999a, ‘Pulsar Rotation Measures and the Magnetic Structure of Our Galaxy’, Monthly Notices Roy. Astron. Soc. 306, 371–380.

    Article  ADS  Google Scholar 

  • Han, J. L., Beck, R., Ehle, M., Haynes, R. F., and Wielebinski, R.: 1999b, ‘Magnetic Fields in the Spiral Galaxy NGC 2997’, Astron. Astrophys. 348, 405–417.

    ADS  Google Scholar 

  • Haslam, C. G. T., Wilson, W. E., Graham, D. A., Hunt, G. C.: 1974, ‘A Further 408 MHz Survey of the Northern Sky’, Astron. Astrophys. Suppl. 13, 359–394.

    ADS  Google Scholar 

  • Haverkorn, M., Katgert, P., and de Bruyn, A. G.: 2000, ‘Structure in the Local Galactic ISM on Scales Down to 1 pc, From Multi-Band Radio Polarization Observations’, Astron. Astrophys. 356, L13 - L16.

    ADS  Google Scholar 

  • Haynes, R. E, Stewart, R. T., Gray, A. D., Reich, W., Reich, P., and Mebold, U.: 1992, ‘Polarized Arcs Near the Galactic Centre’, Astron. Astrophys. 264, 500–512.

    ADS  Google Scholar 

  • Heiles, C.: 1976, ‘The Interstellar Magnetic Field’, Ann. Rev. Astron. Astrophys. 14, 1–22.

    Article  ADS  Google Scholar 

  • Heiles, C.: 1996, in W. G. Roberge and D. C. B. Whittet (eds.), ‘A Comprehensive View of the Galactic Magnetic Field, Especially Near the Sun’, Polarimetry of the Interstellar Medium, ASP Conf. Ser. 97, 457–474.

    Google Scholar 

  • Hummel, E., van Gorkom, J. H., and Kotanyi, C. G.: 1983, ‘Anomalous Radio Continuum Features in Edge-on Spiral Galaxies’, Astrophys. J. 267, L5 — L9.

    Article  ADS  Google Scholar 

  • Indrani, C. and Deshpande, A. A.: 1998, ‘The Large Scale Structure of the Galactic Magnetic Field’, New Astron. 4, 33–40.

    ADS  Google Scholar 

  • Junkes, N., Fürst, E., and Reich, W.: 1987, ‘A Survey of Linear Polarization Along the Galactic Plane’, Astron. Astrophys. Suppl. 69, 451–464.

    ADS  Google Scholar 

  • Krause, M.: 1990, in R. Beck, R. R. Kronberg, and R. Wielebinski (eds.), ‘Multi-frequency Radio Observations of Spiral Galaxies and Their Interpretation’, Galactic and Intergalactic Magnetic Fields, Kluwer Academic Publishers, Dordrecht, pp. 187–196.

    Google Scholar 

  • Lang, C. C., Anantharamaiah, K. R., Kassim, N. E., and Lazio, T. J. W.: 1999, ‘Discovery of a Nonthermal Galactic Center Filament Parallel to the Galactic Plane’, Astrophys. J. 521, L41–44.

    Article  ADS  Google Scholar 

  • Lesch, H. and Reich, W.: 1992, ‘The Origin of Monoenergetic Electrons in the Arc of the Galactic Center. Particle Acceleration by Magnetic Reconnection’, Astron. Astrophys. 264, 493–499.

    ADS  Google Scholar 

  • Minter, A. H. and Spangler, S. R.: 1996, ‘Observation of Turbulent Fluctuations in the Interstellar Plasma Density and Magnetic Field on Spatial Scales of 0.01 to 100 parsecs’, Astrophys. J. 458, 194–214.

    Article  ADS  Google Scholar 

  • Morris, M.: 1994, in R. Genzel and A. I. Harris (eds.), ‘Magnetic Phenomena’, The Nuclei of Normal Galaxies, Kluwer Academic Publishers, Dordrecht, pp. 185–198.

    Google Scholar 

  • Niklas, S.: 1995, ‘Eigenschaften von Spiralgalaxien im hochfrequenten Radiokontinuum’, Ph.D. Thesis, University of Bonn.

    Google Scholar 

  • Niklas, S. and Beck, R.: 1997, ‘A New Approach for the Radio—far Infrared Correlation for Non-calorimeter Galaxies’, Astron. Astrophys. 320, 54–64.

    ADS  Google Scholar 

  • Ohno, H. and Shibata, S.: 1993, ‘The Random Magnetic Field in the Galaxy’, Monthly. Notices Roy. Astron. Soc. 262, 953–962.

    ADS  Google Scholar 

  • Phillipps, S., Kearsey, S., Osborne, J. L., Haslam, C. G. T., and Stoffel, H.: 1981, ‘Distribution of Galactic Synchrotron Emission’, Astron. Astrophys. 98, 286–294.

    ADS  Google Scholar 

  • Plante, R. L., Lo, K. Y., Crutcher, R. M., and Killeen, N. E. B.: 1994, in R. Genzel and A. I. Harris (eds.), ‘The Magnetic Field at the Galactic Center: Detection of HI Zeeman Splitting’, The Nuclei of Normal Galaxies, Kluwer Academic Publishers, Dordrecht, pp. 205–207.

    Google Scholar 

  • Poezd, A., Shukurov, A., and Sokoloff, D.: 1993, ‘Global Magnetic Patterns in the Milky Way and the Andromeda Nebula’, Monthly Notices Roy. Astron. Soc. 264, 285–297.

    ADS  Google Scholar 

  • Pohl, M.: 1993, ‘On the Predictive Power of the Minimum Energy Condition I. Isotropic Steady-state Configurations’, Astron. Astrophys. 270, 91–101.

    ADS  Google Scholar 

  • Pohl, M., Reich, W., and Schlickeiser, R.: 1992, ‘Synchrotron Modelling of the 400 pc Spur at the Galactic Center’, Astron. Astrophys. 262, 441–454.

    ADS  Google Scholar 

  • Rand, R. J. and Kulkarni, S. R.: 1989, ‘The Local Galactic Magnetic Field’, Astrophys. J. 343, 760–772.

    Article  ADS  Google Scholar 

  • Rand, R. J. and Lyne, A. G.: 1994, ‘New Rotation Measures of Distant Pulsars in the Inner Galaxy and Magnetic Field Reversals’, Monthly Notices Roy. Astron. Soc. 268, 497–505.

    ADS  Google Scholar 

  • Reich, W.: 1994, in R. Genzel and A. I. Harris (eds.), ‘High Frequency Radio Observations of Polarized Emission in the Galactic Center’, The Nuclei of Normal Galaxies, Kluwer Academic Publishers, Dordrecht, pp. 55–62.

    Google Scholar 

  • Reich, W., Sofue, Y., and Matsuo, H.: 2000, ‘150 GHz NOBA Observations of the Galactic Center Arc’, Publ. Astron. Soc. Japan 52, 355–361.

    ADS  Google Scholar 

  • Rohde, R., Beck, R., and Elstner, D.: 1999, ‘Magnetic Arms in NGC 6946 Generated by a Turbulent Dynamo’, Astron. Astrophys. 350, 423–433.

    ADS  Google Scholar 

  • Schlickeiser, R.: 1984, ‘An Explanation of Abrupt Cutoffs in the Optical-infrared Spectra of Non-thermal Sources. A New Pile-up Mechanism for Relativistic Electron Spectra’, Astron. Astrophys. 136, 227–236.

    ADS  Google Scholar 

  • Seiradakis, J. H., Lasenby, A. N., Yusef-Zadeh, F., Wielebinski, R., and Klein, U.: 1985, ‘A New

    Google Scholar 

  • Symmetrical Polarization Structure Near the Galactic Centre’, Nature 317 697–699.

    Google Scholar 

  • Simard-Nomandin, M. and Kronberg, P. R: 1980, ‘Rotation Measures and the Galactic Magnetic Field’, Astrophys. J. 242, 74–94.

    Article  ADS  Google Scholar 

  • Sokoloff, D. D., Bykov, A. A., Shukurov, A., Berkhuijsen, E. M., Beck, R., and Poezd, A. D.: 1998, ‘Depolarization and Faraday Effects in Galaxies’, Monthly Notices Roy. Astron. Soc. 299, 189–206

    Article  ADS  Google Scholar 

  • Spoelstra, T. A. Th.: 1977, ‘The Galactic Magnetic Field’, Soviet Phys. Uspekhi 20, 336–342.

    Article  ADS  Google Scholar 

  • Strong, A. W., Moskalenko, I. V., and Reimer, 0.: 2000, ‘Diffuse Continuum Gamma Rays from the Galaxy’, Astrophys. J. 537, 763–784.

    Article  ADS  Google Scholar 

  • Taylor, J. H. and Cordes, J. M.: 1993, ‘Pulsar Distances and the Galactic Distribution of Free Electrons’, Astrophys. J. 411 674–684.

    Google Scholar 

  • Tinbergen, J.: 1996, Astronomical Polarimetry, Cambridge University Press, Cambridge.

    Book  Google Scholar 

  • Tsuboi, M., Inoue, M., Handa, T., Tabara, H., Kato, T., Sofue, Y., and Kaifu, N.: 1986, ‘Prominent

    Google Scholar 

  • Polarized Plumes in the Galactic Center Region and Their Magnetic Field’, Astron. J. 92 818–824.

    Google Scholar 

  • Uchida, K. I. and Gästen, R.: 1995, ‘The Large-Scale Magnetic Field in the Galactic Center’, Astron. Astrophys. 298, 473–481.

    ADS  Google Scholar 

  • Uyaniker, B., Fürst, E., Reich, W., Reich, R, and Wielebinski, R.: 1999, ‘A 1.4 GHz Radio Continuum and Polarization Survey at Medium Galactic Latitudes’, Astron. Astrophys. Suppl. 138, 31–45.

    Article  ADS  Google Scholar 

  • Vallée, J. P.: 1995, ‘The Milky Way’s Spiral Arms Traced by Magnetic Fields, Dust, Gas, and Stars’, Astrophys. J. 454, 119–124.

    Article  ADS  Google Scholar 

  • Vallée, J. R: 1996, ‘Magnetic Field Reversals in the Milky Way — “Cherchez le Champ Magnétique”, Astron. Astrophys. 308, 433–440.

    ADS  Google Scholar 

  • Verschuur, G. L.: 1979, ‘Observations of the Galactic Magnetic Field’, Fund. Cosmic Phys. 5, 113–191.

    ADS  Google Scholar 

  • Yusef-Zadeh, F., Roberts, D. A., Goss, W. M., Frail, D. A., and Green, A. J.: 1996, ‘Detection of 1720 MHz Hydroxyl Masers at the Galactic Center: Evidence for Shock-excited Gas and Milligauss Fields’, Astrophys. J. 466, L25–L29.

    Article  ADS  Google Scholar 

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Beck, R. (2001). Galactic and Extragalactic Magnetic Fields. In: Diehl, R., Parizot, E., Kallenbach, R., Von Steiger, R. (eds) The Astrophysics of Galactic Cosmic Rays. Space Sciences Series of ISSI, vol 13. Springer, Dordrecht. https://doi.org/10.1007/978-94-017-3239-0_21

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  • DOI: https://doi.org/10.1007/978-94-017-3239-0_21

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