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Origin of Galactic and Extragalactic Magnetic Fields

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arxiv astro-ph/0207240 v1 pith:RMPVTSP7 submitted 2002-07-11 astro-ph

classification astro-ph
keywords fieldsmagneticdynamogalaxiesclustersalpha-omegaknownorigin
verification ladder T0 review T1 audit T2 compute T3 formal

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A variety of observations suggest that magnetic fields are present in all galaxies and galaxy clusters. These fields are characterized by a modest strength (10^{-7}-10^{-5} G) and huge spatial scale (~Mpc). It is generally assumed that magnetic fields in spiral galaxies arise from the combined action of differential rotation and helical turbulence, a process known as the alpha-omega dynamo. However fundamental questions concerning the nature of the dynamo as well as the origin of the seed fields necessary to prime it remain unclear. Moreover, the standard alpha-omega dynamo does not explain the existence of magnetic fields in elliptical galaxies and clusters. The author summarizes what is known observationally about magnetic fields in galaxies, clusters, superclusters, and beyond. He then reviews the standard dynamo paradigm, the challenges that have been leveled against it, and several alternative scenarios. He concludes with a discussion of astrophysical and early Universe candidates for seed fields.

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Cited by 14 Pith papers

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score. Full citation record

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    astro-ph.CO 2025-10 unverdicted novelty 7.0 of 10

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  4. Self-Consistent Parker Bound on Magnetic Monopoles

    hep-ph 2026-05 unverdicted novelty 6.0 of 10

    A self-consistent Parker bound on magnetic monopoles is derived using the galactic mean-field dynamo eigenmode and turbulent field seeding and acceleration, producing modified flux limits at low and intermediate masse...

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    hep-ph 2024-12 conditional novelty 6.0 of 10

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  9. Contribution of the chiral vortical effect to the evolution of the hypermagnetic field and the matter-antimatter asymmetry in the early Universe

    hep-ph 2019-08 conditional novelty 6.0 of 10

    A nonzero primordial vorticity seeds a hypermagnetic field from zero in the symmetric phase; the chiral magnetic effect then amplifies it and converts lepton into baryon asymmetry.

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    astro-ph.HE 2026-06 unverdicted novelty 5.0 of 10

    A symbiotic axion-dilaton system sources a moderately chiral dark U(1) magnetic field of astrophysically relevant strength during radiation domination through tachyonic amplification without fine-tuning.

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    astro-ph.CO 2026-05 unverdicted novelty 5.0 of 10

    Updated constraints on neutrino-sustained primordial vector modes imply magnetic fields too weak to seed observations and cannot reproduce the EB power spectrum while satisfying parity-even limits.

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    Primordial black holes formed from magnetically induced density fluctuations could explain all dark matter, but only in a finely tuned parameter window.

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