2006/04/21 by S. Bertone, Serena Bertone, Corina Vogt +3 · 150 citations
Physics and Astronomy · #Active galactic nucleus #Astronomy #Astrophysics #Astrophysics and Cosmic Phenomena #Astrophysics and Star Formation Studies #COSMIC cancer database #Cosmic ray #Dynamo #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy cluster #Intergalactic travel #Interstellar medium #Magnetic field #Physics #Redshift #Seeding #Structure formation #astro-ph
paper · pdf · doi:10.1111/j.1365-2966.2006.10474.x
published in Monthly Notices of the Royal Astronomical Society 370(1), 319-330 (Oxford University Press) · 14 pages, 5 figures. Accepted for publications by MNRAS. A high resolution version of the paper is available at http://astronomy.sussex.ac.uk/~sb207/Papers/bb.ps.gz
arxiv created 2006/04/21 · openalex publication_date 2006/06/06 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The origin of intergalactic magnetic fields is still a mystery and several scenarios have been proposed so far: among them, primordial phase transitions, structure-formation shocks and galactic outflows. In this work, we investigate how efficiently galactic winds can provide an intense and widespread ‘seed’ magnetization. This may be used to explain the magnetic fields observed today in clusters of galaxies and in the intergalactic medium (IGM). We use semi-analytic simulations of magnetized galactic winds coupled to high-resolution N-body simulations of structure formation to estimate lower and upper limits for the fraction of the IGM which can be magnetized up to a specified level. We find that galactic winds are able to seed a substantial fraction of the cosmic volume with magnetic fields. Most regions affected by winds have magnetic fields in the range 10−12 < B < 10−8 G, while higher seed fields can be obtained only rarely and in close proximity to wind-blowing galaxies. These seed fields are sufficiently intense for a moderately efficient turbulent dynamo to amplify them to the observed values. The volume-filling factor of the magnetized regions strongly depends on the efficiency of winds to load mass from the ambient medium. However, winds never completely fill the whole Universe and pristine gas can be found in cosmic voids and regions unaffected by feedback even at z= 0. This means that, in principle, there might be the possibility to probe the existence of primordial magnetic fields in such regions.