METAL: The Metal Evolution, Transport, and Abundance in the Large Magellanic Cloud Hubble program. III. Interstellar Depletions, Dust-to-Metal, and Dust-to-Gas Ratios Versus Metallicity
arXiv:2202.04765 · doi:10.3847/1538-4357/ac5248
Abstract
The metallicity and gas density dependence of interstellar depletions, the dust-to-gas (D/G), and dust-to-metal (D/M) ratios have important implications for how accurately we can trace the chemical enrichment of the universe; either by using FIR dust emission as a tracer of the ISM; or by using spectroscopy of damped Lyman-alpha systems (DLAs) to measure chemical abundances over a wide range of redshifts. We collect and compare large samples of depletion measurements in the Milky Way (MW), LMC (Z=0.5 Zsun), and SMC (Z=0.2 Zsun). The relation between the depletions of different elements do not strongly vary between the three galaxies, implying that abundance ratios should trace depletions accurately down to 20% solar metallicity. From the depletions, we derive D/G and D/M. The D/G increases with density, consistent with the more efficient accretion of gas-phase metals onto dust grains in the denser ISM. For log N(H) > 21 cm^-2, the depletion of metallicity tracers (S, Zn) exceeds -0.5 dex, even at 20% solar metallicity. The gas fraction of metals increases from the MW to the LMC (factor 3) and SMC (factor 6), compensating the reduction in total heavy element abundances and resulting in those three galaxies having the same neutral gas-phase metallicities. The D/G derived from depletions are a factor of 2 (LMC) and 5 (SMC) higher than the D/G derived from FIR, 21 cm, and CO emission, likely due to the combined uncertainties on the dust FIR opacity and on the depletion of carbon and oxygen.
26 pages, 12 figures
References in corpus (18)
- A Unified Representation of Gas-Phase Element Depletions in the Interstellar Medium
- Mass, Metal, and Energy Feedback in Cosmological Simulations
- Metallicity Evolution of Damped Lyman-alpha Systems out to z~5
- The Cosmic Baryon and Metal Cycles
- Dust and Gas in the Magellanic Clouds from the HERITAGE Herschel Key Project. I. Dust Properties and Insights into the Origin of the Submm Excess Emission
- Abundance to age ratios in the HARPS-GTO sample with Gaia DR2: Chemical clocks for a range of [Fe/H]
- Modelling Dust Evolution in Galaxies with a Multiphase, Inhomogeneous ISM
- Dust and Gas in the Magellanic Clouds from the HERITAGE Herschel Key Project. II. Gas-to-Dust Ratio Variations across ISM Phases
- The equilibrium view on dust and metals in galaxies: Galactic outflows drive low dust-to-metal ratios in dwarf galaxies
- The dust budget crisis in high-redshift submillimetre galaxies
- Modeling Dust and Starlight in Galaxies Observed by Spitzer and Herschel: The KINGFISH Sample
- The Polycyclic Aromatic Hydrocarbon Mass Fraction on a 10 pc scale in the Magellanic Clouds
- Low-temperature MIR to submillimeter mass absorption coefficient of interstellar dust analogues II: Mg and Fe-rich amorphous silicates
- METAL: The Metal Evolution, Transport, and Abundance in the Large Magellanic Cloud Hubble program. II. Variations of interstellar depletions and dust-to-gas ratio within the LMC
- METAL: The Metal Evolution, Transport, and Abundance in the Large Magellanic Cloud Hubble program. I. Overview and Initial Results
- Resolving the Dust-to-Metals Ratio and CO-to-H Conversion Factor in the Nearby Universe
- Atomic data for Zn II - Improving Spectral Diagnostics of Chemical Evolution in High-redshift Galaxies
- Galactic dust evolution with rapid dust formation in the interstellar medium due to hypersonic turbulence