Journal article
The role of mergers and interactions in driving the evolution of dwarf galaxies over cosmic time
- Abstract:
- Dwarf galaxies (M⋆ < 109 M⊙) are key drivers of mass assembly in high-mass galaxies, but relatively little is understood about the assembly of dwarf galaxies themselves. Using the NEWHORIZON cosmological simulation (∼40 pc spatial resolution), we investigate how mergers and fly-bys drive the mass assembly and structural evolution of around 1000 field and group dwarfs up to z = 0.5. We find that, while dwarf galaxies often exhibit disturbed morphologies (5 and 20 per cent are disturbed at z = 1 and z = 3 respectively), only a small proportion of the morphological disturbances seen in dwarf galaxies are driven by mergers at any redshift (for 109 M⊙, mergers drive under 20 per cent morphological disturbances). They are instead primarily the result of interactions that do not end in a merger (e.g. fly-bys). Given the large fraction of apparently morphologically disturbed dwarf galaxies which are not, in fact, merging, this finding is particularly important to future studies identifying dwarf mergers and post-mergers morphologically at intermediate and high redshifts. Dwarfs typically undergo one major and one minor merger between z = 5 and z = 0.5, accounting for 10 per cent of their total stellar mass. Mergers can also drive moderate star formation enhancements at lower redshifts (3 or 4 times at z = 1), but this accounts for only a few per cent of stellar mass in the dwarf regime given their infrequency. Non-merger interactions drive significantly smaller star formation enhancements (around two times), but their preponderance relative to mergers means they account for around 10 per cent of stellar mass formed in the dwarf regime.
- Publication status:
- Published
- Peer review status:
- Peer reviewed
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- Files:
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(Preview, Accepted manuscript, 2.2MB, Terms of use)
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- Publisher copy:
- 10.1093/mnras/staa3443
Authors
- Publisher:
- Oxford University Press
- Journal:
- Monthly Notices of the Royal Astronomical Society More from this journal
- Volume:
- 500
- Issue:
- 4
- Pages:
- 4937-4957
- Publication date:
- 2020-11-07
- Acceptance date:
- 2020-10-29
- DOI:
- EISSN:
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1365-2966
- ISSN:
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0035-8711
- Language:
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English
- Keywords:
- Pubs id:
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1122669
- Local pid:
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pubs:1122669
- Deposit date:
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2021-02-22
Terms of use
- Copyright holder:
- Martin, G et al.
- Copyright date:
- 2021
- Rights statement:
- © 2020 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model.
- Notes:
- This is the accepted manuscript version of the article. The final version is available online from Oxford University Press at: https://doi.org/10.1093/mnras/staa3443
- Licence:
- Other
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