Exploring metallicity-dependent rates of Type Ia supernovae and their impact on galaxy formation
Abstract
Type Ia supernovae are critical for feedback and elemental enrichment in galaxies. Recent surveys like the All-Sky Automated Survey for Supernova (ASAS-SN) and the Dark Energy Survey (DES) find that the specific supernova Ia rate at z ~ 0 may be ≲20-50× higher in lower mass galaxies than at Milky Way-mass. Independently, observations show that the close-binary fraction of solar-type Milky Way stars is higher at lower metallicity. Motivated by these observations, we use the FIRE-2 cosmological zoom-in simulations to explore the impact of metallicity-dependent rate models on galaxies of $M_* \sim 10^7\!-\!10^{11}\, \rm {M}_{\odot }$. First, we benchmark our simulated star formation histories against observations, and show that the assumed stellar mass functions play a major role in determining the degree of tension between observations and metallicity-independent rate models, potentially causing ASAS-SN and DES observations to agree more than might appear. Models in which the supernova Ia rate increases with decreasing metallicity ($\propto Z^{-0.5 \,\, \rm {to} \,\, -1}$) provide significantly better agreement with observations. Encouragingly, these rate increases (≳10× in low-mass galaxies) do not significantly impact galaxy masses and morphologies, which remain largely unaffected except for our most extreme models. We explore implications for both [Fe/H] and [$\alpha /\rm {Fe}$] enrichment; metallicity-dependent rate models can improve agreement with the observed stellar mass-metallicity relations in low-mass galaxies. Our results demonstrate that a range of metallicity-dependent rate models are viable for galaxy formation and motivate future work.
- Publication:
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Monthly Notices of the Royal Astronomical Society
- Pub Date:
- October 2022
- DOI:
- 10.1093/mnras/stac2228
- arXiv:
- arXiv:2202.10477
- Bibcode:
- 2022MNRAS.516.1941G
- Keywords:
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- methods: numerical;
- stars: abundances;
- supernovae: general;
- galaxies: formation;
- galaxies: ISM;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 17 pages, 10 figures, 2 appendix figures, 2 tables. Submitted to MNRAS