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The Pandora project – II. How non-thermal physics drives bursty star formation and temperate mass-loaded outflows in dwarf galaxies

Abstract:
Dwarf galaxies provide powerful laboratories for studying galaxy formation physics. Their early assembly, shallow gravitational potentials, and bursty, clustered star formation histories make them especially sensitive to the processes that regulate baryons through multiphase outflows. Using high-resolution, cosmological zoom-in simulations of a dwarf galaxy from the Pandora suite, we explore the impact of stellar radiation, magnetic fields, and cosmic ray feedback on star formation, outflows, and metal retention. We find that our purely hydrodynamical model without non-thermal physics – in which supernova feedback is boosted to reproduce realistic stellar mass assembly – drives violent, overly enriched outflows that suppress the metal content of the host galaxy. Including radiation reduces the clustering of star formation and weakens feedback. However, the additional incorporation of cosmic rays produces fast, mass-loaded, multiphase outflows consisting of both ionized and neutral gas components, in better agreement with observations. These outflows, which entrain a denser, more temperate interstellar medium, exhibit broad metallicity distributions while preserving metals within the galaxy. Furthermore, the star formation history becomes more bursty, in agreement with recent James Webb Space Telescope findings. These results highlight the essential role of non-thermal physics in galaxy evolution and the need to incorporate it in future galaxy formation models.
Publication status:
Published
Peer review status:
Peer reviewed

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Publisher copy:
10.1093/mnras/staf2106

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Author
ORCID:
0000-0002-4059-9850
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Role:
Author
ORCID:
0000-0003-3203-9818
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Role:
Author
ORCID:
0000-0001-6816-0682


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Funder identifier:
https://ror.org/057g20z61
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Funder identifier:
https://ror.org/024mw5h28
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Funder identifier:
https://ror.org/00yjd3n13
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Funder identifier:
https://ror.org/0472cxd90


Publisher:
Oxford University Press
Journal:
Monthly Notices of the Royal Astronomical Society More from this journal
Volume:
545
Issue:
2
Pages:
staf2106
Article number:
staf2106
Publication date:
2025-12-03
Acceptance date:
2025-11-19
DOI:
EISSN:
1365-2966
ISSN:
0035-8711


Language:
English
Keywords:
Pubs id:
2348740
UUID:
uuid_a120c27e-623e-4544-83fe-1e33cae54f88
Local pid:
pubs:2348740
Source identifiers:
3565628
Deposit date:
2025-12-15
ARK identifier:
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