Why do high-redshift galaxies show diverse gas-phase metallicity gradients?

Abstract

Recent spatially resolved observations of galaxies at z=0.6-3 reveal that high-redshift galaxies show complex kinematics and a broad distribution of gas-phase metallicity gradients. To understand these results, we use a suite of high-resolution cosmological zoom-in simulations from the Feedback in Realistic Environments (FIRE) project, which include physically motivated models of the multi-phase ISM, star formation, and stellar feedback. Our simulations reproduce the observed diversity of kinematic properties and metallicity gradients, broadly consistent with observations at z=0-3. Strong negative metallicity gradients only appear in galaxies with a rotating disk, but not all rotationally supported galaxies have significant gradients. Strongly perturbed galaxies with little rotation always have flat gradients. The kinematic properties and metallicity gradient of a high-redshift galaxy can vary significantly on short time-scales, associated with starburst episodes. Feedback from a starburst can destroy the gas disk, drive strong outflows, and flatten a pre-existing negative metallicity gradient. The time variability of a single galaxy is statistically similar to the entire simulated sample, indicating that the observed metallicity gradients in high-redshift galaxies reflect the instantaneous state of the galaxy rather than the accretion and growth history on cosmological time-scales. We find weak dependence of metallicity gradient on stellar mass and specific star formation rate (sSFR). Low-mass galaxies and galaxies with high sSFR tend to have flat gradients, likely due to the fact that feedback is more efficient in these galaxies. We argue that it is important to resolve feedback on small scales in order to produce the diverse metallicity gradients observed.

17 pages, 10 figures, re-submitted to MNRAS after addressing referee's comments

References in corpus (19)

• The Mass-Metallicity Relation at z~2
• The effect of photo-ionization on the cooling rates of enriched, astrophysical plasmas
• A New Calculation of the Ionizing Background Spectrum and the Effects of HeII Reionization
• Chemical enrichment in cosmological, smoothed particle hydrodynamics simulations
• The Cosmic Baryon Cycle and Galaxy Mass Assembly in the FIRE Simulations
• The MOSDEF Survey: Mass, Metallicity, and Star-formation Rate at z~2.3
• Dissipation and Extra Light in Galactic Nuclei: II. 'Cusp' Ellipticals
• Metallicity gradients in local field star-forming galaxies: Insights on inflows, outflows, and the coevolution of gas, stars and metals
• Stellar Population gradients in galaxy discs from the CALIFA survey
• Metal flows of the circumgalactic medium, and the metal budget in galactic halos
• Neutral hydrogen in galaxy halos at the peak of the cosmic star formation history
• The Structure and Dynamical Evolution of the Stellar Disk of a Simulated Milky Way-Mass Galaxy
• Spatially resolved spectroscopy of early-type galaxies over a range in mass
• Colours, Star formation Rates, and Environments of Star forming and Quiescent Galaxies at the Cosmic Noon
• A relationship between specific star formation rate and metallicity gradient within z=1 galaxies from KMOS-HiZELS
• Low-Redshift Lyman Limit Systems as Diagnostics of Cosmological Inflows and Outflows
• The Grism Lens-Amplified Survey from Space (GLASS) X. Sub-kpc resolution gas-phase metallicity maps at cosmic noon behind the Hubble Frontier Fields cluster MACS1149.6+2223
• Scaling Laws of Passive-Scalar Diffusion in the Interstellar Medium
• The spatially resolved stellar populations of isolated early-type galaxies

Cited by in corpus (68)

• FIRE-2 Simulations: Physics versus Numerics in Galaxy Formation
• De Re Metallica: The cosmic chemical evolution of galaxies
• Black Holes on FIRE: Stellar Feedback Limits Early Feeding of Galactic Nuclei
• Be it therefore resolved: Cosmological Simulations of Dwarf Galaxies with Extreme Resolution
• Simulating galaxies in the reionization era with FIRE-2: galaxy scaling relations, stellar mass functions, and luminosity functions
• But What About... Cosmic Rays, Magnetic Fields, Conduction, & Viscosity in Galaxy Formation
• Reconstructing the Last Major Merger of the Milky Way with the H3 Survey
• The Structure and Dynamical Evolution of the Stellar Disk of a Simulated Milky Way-Mass Galaxy
• Cosmic ray feedback in the FIRE simulations: constraining cosmic ray propagation with GeV gamma ray emission
• The origin of the diverse morphologies and kinematics of Milky Way-mass galaxies in the FIRE-2 simulations
• The time-scales probed by star formation rate indicators for realistic, bursty star formation histories from the FIRE simulations
• Consensus report on 25 years of searches for damped Ly$\alpha$ galaxies in emission: Confirming their metallicity-luminosity relation at $z\gtrsim 2$
• Gas accretion and galactic fountain flows in the Auriga cosmological simulations: angular momentum and metal re-distribution
• Self-consistent proto-globular cluster formation in cosmological simulations of high-redshift galaxies
• The KLEVER Survey: Spatially resolved metallicity maps and gradients in a sample of 1.2 < z < 2.5 lensed galaxies
• What Causes The Formation of Disks and End of Bursty Star Formation?
• Gas-phase metallicity gradients of TNG50 star-forming galaxies
• The disc origin of the Milky Way bulge: Dissecting the chemo-morphological relations using N-body simulations and APOGEE
• Cosmic-Ray Driven Outflows to Mpc Scales from $L_{\ast }$ Galaxies
• The physics of gas phase metallicity gradients in galaxies
• Stellar migrations and metal flows -- Chemical evolution of the thin disc of a simulated Milky Way analogous galaxy
• CLEAR: The Gas-Phase Metallicity Gradients of Star-Forming Galaxies at 0.6 < z < 2.6
• Discovery of Strongly Inverted Metallicity Gradients in Dwarf Galaxies at $z$$\sim$2
• The Grism Lens-Amplified Survey from Space (GLASS) X. Sub-kpc resolution gas-phase metallicity maps at cosmic noon behind the Hubble Frontier Fields cluster MACS1149.6+2223
• From 'bathtub' galaxy evolution models to metallicity gradients
• First gas-phase metallicity gradients of $0.1\lesssim z\lesssim 0.8$ galaxies with MUSE
• The bursty origin of the Milky Way thick disc
• Seeds Don't Sink: Even Massive Black Hole "Seeds" Cannot Migrate to Galaxy Centers Efficiently
• Evidence from Disrupted Halo Dwarfs that $r$-process Enrichment via Neutron Star Mergers is Delayed by $\gtrsim 500$ Myrs
• SDSS-IV MaNGA: Modelling the metallicity gradients of gas and stars - radially dependent metal outflow vs IMF
• L-GALAXIES 2020: The evolution of radial metallicity profiles and global metallicities in disc 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
• Early results from GLASS-JWST. IV: Spatially resolved metallicity in a low-mass $z\sim 3$ galaxy with NIRISS
• A Relationship Between Stellar Metallicity Gradients and Galaxy Age in Dwarf Galaxies
• Metallicity gradients in small and nearby spiral galaxies
• On the origin of the mass-metallicity gradient relation in the local Universe
• The evolution of the oxygen abundance gradients in star-forming galaxies in the EAGLE simulations
• Revealing the properties of void galaxies and their assembly using the EAGLE simulation
• GASP and MaNGA surveys shed light on the enigma of the gas metallicity gradients in disk galaxies
• Resolving a dusty, star-forming SHiZELS galaxy at z=2.2 with HST, ALMA and SINFONI on kiloparsec scales
• What the Milky Way bulge reveals about the initial metallicity gradients in the disc
• Spatially Resolved Stellar Spectroscopy of the Ultra-diffuse Galaxy Dragonfly 44. III. Evidence for an Unexpected Star-Formation History
• The effect of gas accretion on the radial gas metallicity profile of simulated galaxies
• Metallicity Gradient of Barred Galaxies with TYPHOON
• A geostatistical analysis of multiscale metallicity variations in galaxies [I]: Introduction and comparison of high-resolution metallicity maps to an analytic metal transport model
• First Census of Gas-phase Metallicity Gradients of Star-forming Galaxies in Overdense Environments at Cosmic Noon
• The Evolution of Gas-Phase Metallicity and Resolved Abundances in Star-forming Galaxies at $z\approx 0.6-1.8$
• Stacked star formation rate profiles of bursty galaxies exhibit 'coherent' star formation
• Spiral Arms are Metal Freeways: Azimuthal Gas-Phase Metallicity Variations in Simulated Cosmological Zoom-in Flocculent Disks
• Cosmic metal density evolution in neutral gas: insights from observations and cosmological simulations
• Gas-phase metallicity break radii of star-forming galaxies in IllustrisTNG
• The interplay between feedback, accretion, transport and winds in setting gas-phase metal distribution in galaxies
• Comparing Models for IMF Variation Across Cosmological Time in Milky Way-like Galaxies
• The role of gas kinematics in setting metallicity gradients at high redshift
• On the deuterium abundance and the importance of stellar mass loss in the interstellar and intergalactic medium
• The Puzzling Origin of Massive Compact Galaxies in MaNGA
• A novel approach to investigate chemical inhomogeneities in GRB host galaxies: The $Z_{\mathrm{abs}}-Z_{\mathrm{emiss}}$ relation
• Damped Lyman-$\alpha$ absorbers and atomic hydrogen in galaxies: the view of the GAEA model
• Exploring the Gas-Phase Metallicity Gradients of Star-forming Galaxies at Cosmic Noon
• Using KCWI to Explore the Chemical Inhomogeneities and Evolution of J1044+0353
• The physical origin of positive metallicity radial gradients in high-redshift galaxies: insights from the FIRE-2 cosmological hydrodynamic simulations
• The internal metallicity distributions of simulated galaxies from EAGLE, Illustris, and IllustrisTNG at z=1.8-4 as probed by Gamma Ray Burst hosts
• Spatially resolved direct method metallicity in a high-redshift analogue local galaxy: temperature structure impact on metallicity gradients
• MASCOT: Molecular gas depletion times and metallicity gradients -- evidence for feedback in quenching active galaxies
• A path towards constraining the evolution of the interstellar medium and outflows in the Milky Way using APOGEE
• The Color Gradients of the Globular Cluster Systems in M87 and M49
• The Stellar Chemical Abundances of Simulated Massive Galaxies at $z=2$
• KURVS: chemical properties from multiple strong line calibrations for star-forming galaxies at $z\sim 1.5$