Abstract
The magnetic field pervading our Galaxy is a crucial constituent of the interstellar medium: it mediates the dynamics of interstellar clouds, the energy density of cosmic rays, and the formation of stars1. The field associated with ionized interstellar gas has been determined through observations of pulsars in our Galaxy. Radio-frequency measurements of pulse dispersion and the rotation of the plane of linear polarization, that is, Faraday rotation, yield an average value for the magnetic field of B ≈ 3 μG (ref. 2). The possible detection of Faraday rotation of linearly polarized photons emitted by high-redshift quasars3 suggests similar magnetic fields are present in foreground galaxies with redshifts z > 1. As Faraday rotation alone, however, determines neither the magnitude nor the redshift of the magnetic field, the strength of galactic magnetic fields at redshifts z > 0 remains uncertain. Here we report a measurement of a magnetic field of B ≈ 84 μG in a galaxy at z = 0.692, using the same Zeeman-splitting technique that revealed an average value of B = 6 μG in the neutral interstellar gas of our Galaxy4. This is unexpected, as the leading theory of magnetic field generation, the mean-field dynamo model, predicts large-scale magnetic fields to be weaker in the past rather than stronger5.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 51 print issues and online access
$199.00 per year
only $3.90 per issue
Buy this article
- Purchase on Springer Link
- Instant access to full article PDF
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
References
Beck, R. in Cosmic Magnetic Fields 41–68 (Lect. Notes Phys. 664, Springer, 2005)
Han, J. L., Manchester, R. N., Lyne, A. G., Qiao, G. J. & van Straten, W. Pulsar rotation measures and the large-scale structure of galactic magnetic fields. Astrophys. J. 642, 868–881 (2006)
Kronberg, P. P. et al. A global probe of cosmic magnetic fields to high redshifts. Astrophys. J. 676, 70–79 (2008)
Heiles, C. & Troland, T. H. The millennium Arecibo 21 centimeter absorption-line survey. III. Techniques for spectral polarization and results for Stokes V . Astrophys. J. Suppl. Ser. 151, 271–297 (2004)
Parker, E. The origin of magnetic fields. Astrophys. J. 160, 383–404 (1970)
Brown, R. L. & Roberts, M. S. 21-centimeter absorption at z = 0.692 in the quasar 3C 286. Astrophys. J. 184, L7–L10 (1973)
Davis, M. M. & May, L. S. New observations of the radio absorption line in 3C 286, with potential application to the direct measurement of cosmological deceleration. Astrophys. J. 219, 1–4 (1978)
Wolfe, A. M., Gawiser, E. & Prochaska, J. X. Damped Lyα systems. Annu. Rev. Astron. Astrophys. 43, 861–918 (2005)
Wolfe, A. M., Broderick, J. J., Condon, J. J. & Johnston, K. J. 3C 286: A cosmological QSO? Astrophys. J. 208, L47–L50 (1976)
Meiring, J. D. et al. Elemental abundance measurements in low-redshift damped Lyα absorbers. Mon. Not. R. Astron. Soc. 370, 43–62 (2006)
Wolfe, A. M., Prochaska, J. X. & Gawiser, E. CII* absorption in damped Lyα systems. I. Star formation rates in a two-phase medium. Astrophys. J. 593, 215–234 (2003)
Boisse, P., Le Brun, V., Bergeron, J. & Deharveng, J.-M. A HST spectroscopic study of QSOs with intermediate redshift damped Lyα systems. Astron. Astrophys. 333, 841–863 (1998)
Kennicutt, R. C. Star formation in galaxies along the Hubble sequence. Annu. Rev. Astron. Astrophys. 36, 189–231 (1998)
Morganti, R. et al. Neutral hydrogen in nearby elliptical and lenticular galaxies: the continuing formation of early-type galaxies. Mon. Not. R. Astron. Soc. 371, 157–169 (2006)
Le Brun, V., Bergeron, J. & Deharveng, J. M. The nature of intermediate-redshift damped Lyα absorbers. Astron. Astrophys. 321, 733–748 (1997)
Steidel, C. C., Pettini, M., Dickinson, M. & Persson, S. E. Imaging of two damped Lyman-alpha absorbers at intermediate redshifts. Astron. J. 108, 2046–2053 (1994)
McKee, C. F. & Ostriker, J. P. A theory of the interstellar medium: three components regulated by supernova explosions in an inhomogeneous substrate. Astrophys. J. 218, 148–169 (1977)
Morganti, R., Greenhill, L. J., Peck, A. B., Jones, D. L. & Henkel, C. Disks, tori, and cocoons: emission and absorption diagnostics of AGN environments. N. Astron. Rev. 48, 1195–1209 (2004)
Lotz, J. M. et al. The evolution of galaxy mergers and morphology at z 1.2 in the extended Groth strip. Astrophys. J. 672, 177–197 (2008)
Bernet, M. L., Miniati, F., Lilly, S. J., Kronberg, P. P. & Dessauges–Zavadsky, M. Strong magnetic fields in normal galaxies at high redshift. Nature 454, 302–304 (2008)
Rees, M. J. Origin of cosmic magnetic fields. Astron. Nachr. 327, 395–398 (2006)
Wolfe, A. M. & Chen, H.-W. Searching for low surface brightness galaxies in the Hubble ultra deep field: implications for the star formation efficiency in neutral gas at z ∼ 3. Astrophys. J. 652, 981–993 (2006)
Heiles, C. Cross-correlation spectropolarimetry in single-dish radio astronomy. Publ. Astron. Soc. Pacif. 113, 1243–1246 (2001)
Baym, G. Lectures on Quantum Mechanics Ch. 1 (Benjamin, 1981)
Savage, B. D. & Sembach, K. R. Interstellar abundances from absorption- line observations with the Hubble-Space Telescope. Annu. Rev. Astron. Astrophys. 34, 279–329 (1996)
Acknowledgements
We wish to thank F. H. Shu for suggesting the merger model and H.-W. Chen for providing us with her reanalysed images of 3C 286. We also thank F. H. Shu, E. Gawiser and A. Lazarian for comments and the US National Science Foundation for financial support. The GBT is one of the facilities of the National Radio Astronomy Observatory, which is a center of the National Science Foundation operated under cooperative agreement by Associated Observatories, Inc. A.M.W., R.A.J. and J.X.P. are Visiting Astronomers at the W. M. Keck Telescope. The Keck Observatory is a joint facility of the University of California, the California Institute of Technology and the National Aeronautics and Space Administration.
Author information
Authors and Affiliations
Corresponding author
PowerPoint slides
Rights and permissions
About this article
Cite this article
Wolfe, A., Jorgenson, R., Robishaw, T. et al. An 84-μG magnetic field in a galaxy at redshift z = 0.692. Nature 455, 638–640 (2008). https://doi.org/10.1038/nature07264
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1038/nature07264
This article is cited by
-
A non-perturbative study of the evolution of cosmic magnetised sources
General Relativity and Gravitation (2016)
-
Magnetic Fields in Cosmic Particle Acceleration Sources
Space Science Reviews (2012)
Comments
By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.