Spatially Resolved Gas-phase Metallicity in FIRE-2 Dwarfs: Late-Time Evolution of Metallicity Relations in Simulations with Feedback and Mergers

Abstract

We present an analysis of spatially resolved gas-phase metallicity relations in five dwarf galaxies ($M_{halo}\approx 10^{11}{M}_{\odot }$, $M_{\star }\approx 10^{8.8}-10^{9.6}{M}_{\odot }$) from the FIRE-2 (Feedback in Realistic Environments) cosmological zoom-in simulation suite, which include an explicit model for sub-grid turbulent mixing of metals in gas, near $z\approx 0$, over a period of 1.4 Gyrs, and compare our findings with observations. While these dwarf galaxies represent a diverse sample, we find that all simulated galaxies match the observed mass-metallicity (MZR) and mass-metallicity gradient (MZGR) relations. We note that in all five galaxies, the metallicities are effectively identical between phases of the interstellar medium (ISM), with 95$\%$ being within $\pm$0.1 dex between various ISM phases, including the cold and dense gas ($T<500$ K and $n_{\mathrm{H}}>1$ cm${}^{-3}$), ionized gas (near the H$\alpha$ $T\approx 10^4$ K ridge-line), and nebular regions (ionized gas where the 10 Myr-averaged star formation rate is non-zero). We find that most of the scatter in relative metallicity between cold and dense gas and ionized gas/nebular regions can be attributed to either local starburst events or metal-poor inflows. We also note the presence of a major merger in one of our galaxies, m11e, with a substantial impact on the metallicity distribution in the spatially resolved map, showing two strong metallicity peaks and triggering a starburst in the main galaxy.

14 pages, 10 figures, submitted to MNRAS

References in corpus (38)

• Chemical enrichment in cosmological, smoothed particle hydrodynamics simulations
• The stellar mass assembly of galaxies from z=0 to z=4. Analysis of a sample selected in the rest-frame near-infrared with Spitzer
• The Origin of the Galaxy Mass-Metallicity Relation and Implications for Galactic Outflows
• The Effects of Stellar Rotation. II. A Comprehensive Set of Starburst99 Models
• Clues to the Origin of the Mass-Metallicity Relation: Dependence on Star Formation Rate and Galaxy Size
• The MOSDEF Survey: The Evolution of the Mass-Metallicity Relation from $z=0$ to $z\sim 3.3$
• The Metallicity of Galaxy Disks: Infall versus Outflow
• A Possible Origin of the Mass-Metallicity Relation of Galaxies
• The VMC Survey - XIV. First results on the look-back time star-formation rate tomography of the Small Magellanic Cloud
• A Critical Look at the Mass-Metallicity-SFR Relation in the Local Universe. I. An Improved Analysis Framework and Confounding Systematics
• The time-scales probed by star formation rate indicators for realistic, bursty star formation histories from the FIRE simulations
• The mass-metallicity relation of interacting galaxies
• The SAMI Galaxy Survey: Exploring the gas-phase Mass-Metallicity Relation
• Carbon and oxygen in HII regions of the Magellanic Clouds: abundance discrepancy and chemical evolution
• Gas-phase metallicity gradients of TNG50 star-forming galaxies
• Separate ways: The Mass-Metallicity Relation does not strongly correlate with Star Formation Rate in SDSS-IV MaNGA galaxies
• Effects of the galactic winds on the stellar metallicity distribution of dwarf spheroidal galaxies
• The total mass and dark halo properties of the Small Magellanic Cloud
• Dense gas is not enough: environmental variations in the star formation efficiency of dense molecular gas at 100pc scales in M51
• A Characteristic Mass Scale in the Mass-Metallicity Relation of Galaxies
• 3-D gas-phase elemental abundances across the formation histories of Milky Way-mass galaxies in the FIRE simulations: initial conditions for chemical tagging
• A Relationship Between Stellar Metallicity Gradients and Galaxy Age in Dwarf Galaxies
• On the origin of the mass-metallicity gradient relation in the local Universe
• METAL: The Metal Evolution, Transport, and Abundance in the Large Magellanic Cloud Hubble program. I. Overview and Initial Results
• An Improved Technique for Measurement of Cold HI in Molecular Cloud Cores
• The mass-metallicity relation of zCOSMOS galaxies at z ~ 0.7, its dependence on SFR, and the existence of massive low-metallicity galaxies
• The spatially resolved star formation history of mergers: A comparative study of the LIRGs IC1623, NGC6090, NGC2623, and Mice
• Mixing matters
• Kiloparsec-scale Variations in the Star Formation Efficiency of Dense Gas: the Antennae Galaxies (NGC 4038/39)
• Mass-metallicity relation of dwarf galaxies and its dependency on time: clues from resolved systems and comparison with massive galaxies
• Diffuse Far-ultraviolet Observations of the Taurus Region
• The formation of the young massive cluster B1 in the Antennae galaxies (NGC 4038/NGC 4039) triggered by cloud-cloud collision
• On the connection between galactic downsizing and the most fundamental galactic scaling relations
• SDSS-IV MaNGA: the "G-dwarf problem" revisited
• The G-dwarf distribution in star-forming galaxies: a tug-of-war between infall and outflow
• Witnessing gas mixing in the metal distribution of the Hickson Compact Group HCG 31
• Predictions for Complex Distributions of Stellar Elemental Abundances in Low-Mass Galaxies
• Diagnosing Turbulence in the Neutral and Molecular Interstellar Medium of Galaxies

Cited by in corpus (1)

• Spiral Arms are Metal Freeways: Azimuthal Gas-Phase Metallicity Variations in Simulated Cosmological Zoom-in Flocculent Disks