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Abstract We present a suite of six high-resolution chemodynamical simulations of isolated galaxies, spanning observed disk-dominated environments on the star-forming main sequence, as well as quenched, bulge-dominated environments. We compare and contrast the physics driving star formation and stellar feedback among the galaxies, with a view to modeling these processes in cosmological simulations. We find that the mass loading of galactic outflows is coupled to the clustering of supernova explosions, which varies strongly with the rate of galactic rotation Ω =vcirc/Rvia the Toomre length, leading to smoother gas disks in the bulge-dominated galaxies. This sets an equation of state in the star-forming gas that also varies strongly with Ω, so that the bulge-dominated galaxies have higher midplane densities, lower velocity dispersions, and higher molecular gas fractions than their main-sequence counterparts. The star formation rate in five out of six galaxies is independent of Ω and is consistent with regulation by the midplane gas pressure alone. In the sixth galaxy, which has the most centrally concentrated bulge and thus the highest Ω, we reproduce dynamical suppression of the star formation efficiency in agreement with observations. This produces a transition away from pressure-regulated star formation.
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Stellar Mass-to-light Ratios: Composite Bulge+Disk Models and the Baryonic Tully–Fisher Relation
Abstract We present stellar population models to calculate the mass-to-light ratio (ϒ * ) based on galaxies’ colors ranging from GALEX far-UV to Spitzer IRAC1 at 3.6 μ m. We present a new composite bulge+disk ϒ * model that considers the varying contribution from bulges and disks based on their optical and near-IR colors. Using these colors, we build plausible star formation histories and chemical enrichment scenarios based on the star formation rate–stellar mass and mass–metallicity correlations for star-forming galaxies. The most accurate prescription is to use the actual colors for the bulge and disk components to constrain ϒ * ; however, a reasonable bulge+disk model plus total color only introduces 5% more uncertainty. Full bulge+disk ϒ * prescriptions applied to the baryonic Tully–Fisher relation improve the linearity of the correlation, increase the slope, and reduce the total scatter by 4%.
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- Award ID(s):
- 1911909
- PAR ID:
- 10428585
- Date Published:
- Journal Name:
- The Astronomical Journal
- Volume:
- 163
- Issue:
- 4
- ISSN:
- 0004-6256
- Page Range / eLocation ID:
- 154
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.3847/1538-3881/ac5249
