Journal article
The resolved star-formation efficiency of early-type galaxies
- Abstract:
- Understanding how and why star formation varies between galaxies is fundamental to our comprehension of galaxy evolution. In particular, the star-formation efficiency (SFE; star-formation rate or SFR per unit cold gas mass) has been shown to vary substantially both across and within galaxies. Early-type galaxies (ETGs) constitute an extreme case, as about a quarter have detectable molecular gas reservoirs but little to no detectable star formation. In this work, we present a spatially resolved view of the SFE in 10 ETGs, combining state-of-the-art Atacama Large Millimeter/submillimeter Array (ALMA) and Multi Unit Spectroscopic Explorer (MUSE) observations. Optical spectroscopic line diagnostics are used to identify the ionized emission regions dominated by star formation, and reject regions where the ionization arises primarily from other sources. We identify very few regions where the ionization is consistent with pure star formation. Using Hα as our SFR tracer, we find that previous integrated measurements of the star-formation rate based on UV and 22 μm emission are systematically higher than the SFR measured from Hα. However, for the small number of regions where ionization is primarily associated with star formation, the SFEs are around 0.4 dex higher than those measured in star-forming galaxies at a similar spatial resolution (with depletion times ranging from 108 to 1010 yr). Whilst the SFE of ETGs is overall low, we find that the SFEs of individual regions within ETGs can be similar to, or higher than, similar sized regions within star-forming galaxies.
- Publication status:
- Published
- Peer review status:
- Peer reviewed
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(Preview, Version of record, pdf, 15.6MB, Terms of use)
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- Publisher copy:
- 10.1093/mnras/staf498
Authors
+ European Research Council
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- Funder identifier:
- https://ror.org/0472cxd90
- Grant:
- 855130
+ National Science and Technology Council
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- Funder identifier:
- https://ror.org/02kv4zf79
- Grant:
- 113-2112-M-032-014-MY3
+ Deutsche Forschungsgemeinschaft
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- Funder identifier:
- https://ror.org/018mejw64
- Grant:
- 500700252
+ Science and Technology Facilities Council
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- Funder identifier:
- https://ror.org/057g20z61
- Grant:
- ST/W000903/1
- ST/Y001133/1
- ST/S000488/1
+ Bundesministerium für Wirtschaft und Energie
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- Funder identifier:
- https://ror.org/02vgg2808
- Grant:
- 50OO2206
- Publisher:
- Oxford University Press
- Journal:
- Monthly Notices of the Royal Astronomical Society More from this journal
- Volume:
- 538
- Issue:
- 4
- Pages:
- 3219–3246
- Article number:
- staf498
- Publication date:
- 2025-03-26
- Acceptance date:
- 2025-03-21
- DOI:
- EISSN:
-
1365-2966
- ISSN:
-
0035-8711
- Language:
-
English
- Keywords:
- Pubs id:
-
2101856
- Local pid:
-
pubs:2101856
- Deposit date:
-
2025-06-12
- ARK identifier:
Terms of use
- Copyright holder:
- Williams et al.
- Copyright date:
- 2025
- Rights statement:
- © 2025 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
- Licence:
- CC Attribution (CC BY)
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