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Evolution of galactic magnetic fields

Lookup NU author(s): Dr Luiz Felippe RodriguesORCiD, Dr Luke Chamandy, Professor Anvar ShukurovORCiD



This is the authors' accepted manuscript of an article that has been published in its final definitive form by Oxford University Press, 2019.

For re-use rights please refer to the publisher's terms and conditions.


We study the cosmic evolution of the magnetic fields of a large sample of spiral galaxies in a cosmologically representative volume by employing a semi-analytic galaxy formation model and numerical dynamo solver in tandem. We start by deriving time- and radius-dependent galaxy properties using the galform galaxy formation model, which are then fed into the nonlinear mean-field dynamo equations. These are solved to give the large-scale (mean) field as a function of time and galactocentric radius for a thin disc, assuming axial symmetry. A simple prescription for the evolution of the small-scale (random) magnetic field component is also adopted. We find that, while most massive galaxies are predicted to have large-scale magnetic fields at redshift z=0, a significant fraction of them are expected to contain negligible large-scale field. Our model indicates that, for most of the galaxies containing large-scale magnetic fields today, the mean-field dynamo becomes active at z<3. We compute the radial profiles of pitch angle, and find broad agreement with observational data for nearby galaxies.

Publication metadata

Author(s): Rodrigues LFS, Chamandy L, Shukurov A, Baugh CM, Taylor AR

Publication type: Article

Publication status: Published

Journal: Monthly Notices of the Royal Astronomical Society

Year: 2019

Volume: 483

Issue: 2

Pages: 2424-2440

Print publication date: 21/02/2019

Online publication date: 30/11/2018

Acceptance date: 28/11/2018

Date deposited: 28/01/2019

ISSN (print): 0035-8711

ISSN (electronic): 1365-2966

Publisher: Oxford University Press


DOI: 10.1093/mnras/sty3270


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