2000/01/24 by Stirling A. Colgate, Hui Li, Colgate, Stirling A. +1 · 1 citation
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysical Phenomena and Observations #Astrophysics (astro-ph) #FOS: Physical sciences #Solar and Space Plasma Dynamics #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/0001418
10 pages, 1 figure (figures.png), invited talk at IAU 195
arxiv created 2000/01/24 · openalex publication_date 2000/01/24 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Recent rotation measure observations of a dozen or so galaxy clusters have revealed a surprisingly large amount of magnetic fields, whose estimated energy and flux are, on average, ∼ 1058 ergs and ∼ 1041 G cm2, respectively. These quantities are so much larger than any coherent sums of individual galaxies within the cluster that an efficient galactic dynamo is required. We associate these fields with single AGNs within the cluster and therefore with all galaxies during their AGN phase. Only the central, massive black hole (BH) has the necessary binding energy, ∼ 1061 ergs. Only the accretion disk during the BH formation has the winding number, ∼ 1011 turns, necessary to make the gain and magnetic flux. We present a model of the BH accretion disk dynamo that might create these magnetic fields, where the helicity of the α- Ω dynamo is driven by star-disk collisions. The back reaction of the saturated dynamo forms a force-free field helix that carries the energy and flux of the dynamo and redistributes them within the clusters.