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Environment matters: stronger magnetic fields in satellite galaxies

Werhahn, Maria, Pakmor, Rüdiger, Bieri, Rebekka, van de Voort, Freeke ORCID: https://orcid.org/0000-0002-6301-638X, Talbot, Rosie Y. and Springel, Volker 2025. Environment matters: stronger magnetic fields in satellite galaxies. Monthly Notices of the Royal Astronomical Society 10.1093/mnras/staf873

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Abstract

Magnetic fields are ubiquitous in the universe and an important component of the interstellar medium. It is crucial to accurately model and understand their properties in different environments and across all mass ranges of galaxies to interpret observables related to magnetic fields correctly. However, the assessment of the role of magnetic fields in galaxy evolution is often hampered by limited numerical resolution in cosmological simulations, in particular for satellite galaxies. To this end, we study the magnetic fields in high-resolution cosmological zoom simulations of disk galaxies (with M200 ≈ 1010 to 1013 M⊙) and their satellites within the Auriga galaxy formation model including cosmic rays. We find significantly higher magnetic field strengths in satellite galaxies compared to isolated dwarfs with a similar mass or star-formation rate, in particular after they had their first close encounter with their host galaxy. These are stronger on average by factors of 2 to 8 when compared at the same total mass, with a large scatter, ranging up to factors of ∼15. While this result is ubiquitous and independent of resolution in the satellites that are past their first infall, there seems to be a wide range of amplification mechanisms acting together. Our result highlights the importance of considering the environment of dwarf galaxies when interpreting their magnetic field properties as well as related observables such as their gamma-ray and radio emission, the latter being particularly relevant for future observations such as with the SKA observatory.

Item Type: Article
Date Type: Published Online
Status: In Press
Schools: Schools > Physics and Astronomy
Publisher: Oxford University Press
ISSN: 0035-8711
Date of First Compliant Deposit: 9 June 2025
Date of Acceptance: 23 May 2025
Last Modified: 19 Jun 2025 13:19
URI: https://orca.cardiff.ac.uk/id/eprint/178924

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