CO Emission, Molecular Gas, and Metallicity in Main-Sequence Star-Forming Galaxies at $z\sim 2.3$

Abstract

We present observations of CO(3-2) in 13 main-sequence $z=2.0-2.5$ star-forming galaxies at $\log (M_{\ast }/M_{\odot })=10.2-10.6$ that span a wide range in metallicity (O/H) based on rest-optical spectroscopy. We find that CO(3-2)/SFR decreases with decreasing metallicity, implying that the CO luminosity per unit gas mass is lower in low-metallicity galaxies at $z\sim 2$. We constrain the CO-to-H${}_2$ conversion factor (${\alpha }_{\text{CO}}$) and find that ${\alpha }_{\text{CO}}$ inversely correlates with metallicity at $z\sim 2$. We derive molecular gas masses ($M_{\text{mol}}$) and characterize the relations among $M_{\ast }$, SFR, $M_{\text{mol}}$, and metallicity. At $z\sim 2$, $M_{\text{mol}}$ increases and molecular gas fraction ($M_{\text{mol}}$/$M_{\ast }$) decrease with increasing $M_{\ast }$, with a significant secondary dependence on SFR. Galaxies at $z\sim 2$ lie on a near-linear molecular KS law that is well-described by a constant depletion time of 700 Myr. We find that the scatter about the mean SFR-$M_{\ast }$, O/H-$M_{\ast }$, and $M_{\text{mol}}$-$M_{\ast }$ relations is correlated such that, at fixed $M_{\ast }$, $z\sim 2$ galaxies with larger $M_{\text{mol}}$ have higher SFR and lower O/H. We thus confirm the existence of a fundamental metallicity relation at $z\sim 2$ where O/H is inversely correlated with both SFR and $M_{\text{mol}}$ at fixed $M_{\ast }$. These results suggest that the scatter of the $z\sim 2$ star-forming main sequence, mass-metallicity relation, and $M_{\text{mol}}$-$M_{\ast }$ relation are primarily driven by stochastic variations in gas inflow rates. We place constraints on the mass loading of galactic outflows and perform a metal budget analysis, finding that massive $z\sim 2$ star-forming galaxies retain only 30% of metals produced, implying that a large mass of metals resides in the circumgalactic medium.

arXiv comment35 pages, 17 figures, submitted to ApJ

References in corpus (183)

• Galactic Stellar and Substellar Initial Mass Function
• Star Formation in Galaxies Along the Hubble Sequence
• The Dust Content and Opacity of Actively Star-Forming Galaxies
• Cosmic Star Formation History
• The Origin of the Mass--Metallicity Relation: Insights from 53,000 Star-Forming Galaxies in the SDSS
• The physical properties of star forming galaxies in the low redshift universe
• The CO-to-H2 Conversion Factor
• CANDELS: The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey
• CANDELS: The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey - The Hubble Space Telescope Observations, Imaging Data Products and Mosaics
• Star Formation in AEGIS Field Galaxies since z=1.1 : The Dominance of Gradually Declining Star Formation, and the Main Sequence of Star-Forming Galaxies
• The Star Formation Efficiency in Nearby Galaxies: Measuring Where Gas Forms Stars Effectively
• The propagation of uncertainties in stellar population synthesis modeling I: The relevance of uncertain aspects of stellar evolution and the IMF to the derived physical properties of galaxies
• The Star Formation Law in Nearby Galaxies on Sub-Kpc Scales
• [O III]/[N II] as an Abundance Indicator at High Redshift
• A Highly Consistent Framework for the Evolution of the Star-Forming "Main Sequence" from z~0-6
• 3D-HST+CANDELS: The Evolution of the Galaxy Size-Mass Distribution since $z=3$
• The Environmental Dependence of the Relations between Stellar Mass, Structure, Star Formation and Nuclear Activity in Galaxies
• The Co-Evolution of Galaxies and Supermassive Black Holes: Insights from Surveys of the Contemporary Universe
• The SAURON project - IV. The mass-to-light ratio, the virial mass estimator and the fundamental plane of elliptical and lenticular galaxies
• Simba: Cosmological Simulations with Black Hole Growth and Feedback
• A fundamental relation between mass, SFR and metallicity in local and high redshift galaxies
• The Mass-Metallicity Relation at z~2
• The Structure and Kinematics of the Circum-Galactic Medium from Far-UV Spectra of z~2-3 Galaxies
• An ultra-deep near-infrared spectrum of a compact quiescent galaxy at z=2.2
• First Results from the TNG50 Simulation: Galactic outflows driven by supernovae and black hole feedback
• 3D-HST WFC3-selected Photometric Catalogs in the Five CANDELS/3D-HST Fields: Photometry, Photometric Redshifts and Stellar Masses
• AMAZE. I. The evolution of the mass-metallicity relation at z>3
• High molecular gas fractions in normal massive star forming galaxies in the young Universe
• PHIBSS: molecular gas content and scaling relations in z~1-3 normal star forming galaxies
• The Molecular Interstellar Medium in Ultraluminous Infrared Galaxies
• Very High Gas Fractions and Extended Gas Reservoirs in z=1.5 Disk Galaxies
• Gas-regulation of galaxies: the evolution of the cosmic sSFR, the metallicity-mass-SFR relation and the stellar content of haloes
• Constraining the Low-Mass Slope of the Star Formation Sequence at 0.5<z<2.5
• The Rest Frame Optical Spectra of Lyman Break Galaxies: Star Formation, Extinction, Abundances, and Kinematics
• Submillimeter Galaxies at z~2: Evidence for Major Mergers & Constraints on Lifetimes, IMF and CO-H2 Conversion Factor
• The 3D-HST Survey: Hubble Space Telescope WFC3/G141 grism spectra, redshifts, and emission line measurements for $\sim 100,000$ galaxies
• The chemical make-up of the Sun: A 2020 vision
• The Dark Molecular Gas
• 3D-HST: A wide-field grism spectroscopic survey with the Hubble Space Telescope
• Gusty, gaseous flows of FIRE: galactic winds in cosmological simulations with explicit stellar feedback
• PHIBSS: Unified Scaling Relations of Gas Depletion Time and Molecular Gas Fractions
• Combined CO & Dust Scaling Relations of Depletion Time and Molecular Gas Fractions with Cosmic Time, Specific Star Formation Rate and Stellar Mass
• Dust-Corrected Star Formation Rates of Galaxies. II. Combinations of Ultraviolet and Infrared Tracers
• Strong Nebular Line Ratios in the Spectra of z~2-3 Star-forming Galaxies: First Results from KBSS-MOSFIRE
• The CO-to-H2 Conversion Factor and Dust-to-Gas Ratio on Kiloparsec Scales in Nearby Galaxies
• The O3N2 and N2 abundance indicators revisited: improved calibrations based on CALIFA and Te-based literature data
• The Mass-Metallicity Relation with the Direct Method on Stacked Spectra of SDSS Galaxies
• The Evolving Interstellar Medium of Star Forming Galaxies Since z=2 as Probed by Their Infrared Spectral Energy Distributions
• The Stellar, Gas and Dynamical Masses of Star-Forming Galaxies at z~2
• xCOLD GASS: the complete IRAM-30m legacy survey of molecular gas for galaxy evolution studies
• ISM masses and the star formation law at Z = 1 to 6 // ALMA observations of dust continuum in 145 galaxies in the COSMOS survey field
• An interferometric CO survey of luminous submm galaxies
• An Analytic Model for the Evolution of the Stellar, Gas, and Metal Content of Galaxies
• The Origin of the Galaxy Mass-Metallicity Relation and Implications for Galactic Outflows
• SINFONI Integral Field Spectroscopy of z~2 UV-selected Galaxies: Rotation Curves and Dynamical Evolution
• Star formation efficiency in galaxy interactions and mergers: a statistical study
• The Evolution of the Star-forming Interstellar Medium across Cosmic Time
• The MOSFIRE Deep Evolution Field (MOSDEF) Survey: Rest-Frame Optical Spectroscopy for ~1500 H-Selected Galaxies at 1.37 < z < 3.8
• The Origin and Evolution of the Galaxy Mass-Metallicity Relation
• The Cosmic Baryon Cycle and Galaxy Mass Assembly in the FIRE Simulations
• Reconciling the Stellar and Nebular Spectra of High Redshift Galaxies
• A fundamental plane for field star-forming galaxies
• The Mass-Metallicity and the Fundamental Metallicity Relation revisited on a fully Te-based abundance scale for galaxies
• Black hole variability and the star formation-AGN connection: Do all star-forming galaxies host an AGN?
• Dust Obscuration and Metallicity at High Redshift: New Inferences from UV, H-alpha, and 8 Micron Observations of z~2 Star-Forming Galaxies
• Regularity underlying complexity: a redshift-independent description of the continuous variation of galaxy-scale molecular gas properties in the mass-star formation rate plane
• Evolution of Interstellar Medium, Star Formation, and Accretion at High Redshift
• A Budget and Accounting of Metals at z~0: Results from the COS-Halos Survey
• The MOSDEF Survey: Electron Density and Ionization Parameter at $z\sim 2.3$
• The Characteristic Star Formation Histories of Galaxies at Redshifts z~2-7
• New fully empirical calibrations of strong-line metallicity indicators in star forming galaxies
• Strongly baryon-dominated disk galaxies at the peak of galaxy formation ten billion years ago
• The Metallicity Dependence of the CO-to-H${}_2$ Conversion Factor from Observations of Local Group Galaxies
• The metallicity dependence of the CO {\rightarrow} H_2 conversion factor in z>1 star forming galaxies
• CO excitation of normal star forming galaxies out to z=1.5 as regulated by the properties of their interstellar medium
• The Connection Between Galaxies and Intergalactic Absorption Lines at Redshift 2<z<3
• The MOSDEF Survey: The Evolution of the Mass-Metallicity Relation from $z=0$ to $z\sim 3.3$
• Validation of the equilibrium model for galaxy evolution to z~3 through molecular gas and dust observations of lensed star-forming galaxies
• Molecular and atomic gas along and across the main sequence of star-forming galaxies
• Nebular Emission Line Ratios in z~2-3 Star-Forming Galaxies with KBSS-MOSFIRE: Exploring the Impact of Ionization, Excitation, and Nitrogen-to-Oxygen Ratio
• Low CO Luminosities in Dwarf Galaxies
• On the Relationship Between Molecular Hydrogen and Carbon Monoxide Abundances in Molecular Clouds
• The ISM in distant star-forming galaxies: Turbulent pressure, fragmentation and cloud scaling relations in a dense gas disk at z=2.3
• The MOSDEF Survey: Mass, Metallicity, and Star-formation Rate at z~2.3
• Metallicity evolution, metallicity gradients and gas fractions at z~3.4
• Cosmic evolution of the atomic and molecular gas content of galaxies
• The relation between metallicity, stellar mass and star formation in galaxies: an analysis of observational and model data
• The MOSDEF Survey: Excitation Properties of $z\sim 2.3$ Star-forming Galaxies
• How stellar feedback simultaneously regulates star formation and drives outflows
• The Mass-Metallicity and Luminosity-Metallicity Relation from DEEP2 at z ~ 0.8
• The SINS/zC-SINF survey of z~2 galaxy kinematics: SINFONI adaptive optics-assisted data and kiloparsec-scale emission line properties
• Constraints on star-formation driven galaxy winds from the mass-metallicity relation at z=0
• The evolution of the mass-metallicity relation in IllustrisTNG
• A systematic metallicity study of DustPedia galaxies reveals evolution in the dust-to-metal ratios
• The KMOS^3D Survey: Demographics and Properties of Galactic Outflows at z = 0.6 - 2.7
• The cold interstellar medium of galaxies in the Local Universe
• Bimodality of low-redshift circumgalactic O VI in non-equilibrium EAGLE zoom simulations
• Evolution of the atomic and molecular gas content of galaxies
• A fundamental relation between the metallicity, gas content, and stellar mass of local galaxies
• The MOSDEF Survey: Direct-Method Metallicities and ISM Conditions at $z\sim 1.5-3.5$
• The role of cold gas and environment on the stellar mass - metallicity relation of nearby galaxies
• Evidence for Solar Metallicities in Massive Star-forming Galaxies at z>~2
• Rest-Frame Optical Spectra of Three Strongly Lensed Galaxies at z~2
• Tracing Inflows and Outflows with Absorption Lines in Circumgalactic Gas
• Metal flows of the circumgalactic medium, and the metal budget in galactic halos
• The FMOS-Cosmos Survey of Star-Forming Galaxies at z~1.6 II. The Mass-Metallicity Relation and the Dependence on Star Formation Rate and Dust Extinction
• The ALMA Spectroscopic Survey in the HUDF: CO luminosity functions and the molecular gas content of galaxies through cosmic history
• The MOSDEF Survey: Optical AGN Diagnostics at z~2.3
• Dust temperature and CO-to-H2 conversion factor variations in the SFR-M* plane
• The Properties of the Interstellar Medium within a Star-Forming Galaxy at z=2.3
• The Rest-Frame Optical Spectrum of MS 1512-cB58
• Deriving a multivariate CO-to-H${}_2$ conversion function using the [CII]/CO(1-0) ratio and its application to molecular gas scaling relations
• MUFASA: Galaxy star formation, gas, and metal properties across cosmic time
• The MOSDEF survey: a stellar mass-SFR-metallicity relation exists at $z\sim 2.3$
• The physics of the fundamental metallicity relation
• "Direct" Gas-Phase Metallicity in Local Analogs of High-Redshift Galaxies: Empirical Metallicity Calibrations for High-Redshift Star-Forming Galaxies
• From haloes to Galaxies - I. The dynamics of the gas regulator model and the implied cosmic sSFR history
• Galaxy metallicity scaling relations in the EAGLE simulations
• The MOSDEF Survey: Significant Evolution in the Rest-Frame Optical Emission Line Equivalent Widths of Star-Forming Galaxies at z=1.4-3.8
• Automated Mining of the ALMA Archive in the COSMOS Field (A3COSMOS): II. Cold Molecular Gas Evolution out to Redshift 6
• Revisiting the Integrated Star Formation Law. Paper I: Non-Starbursting Galaxies
• Galactic outflow rates in the EAGLE simulations
• Measuring the Physical Conditions in High-Redshift Star-Forming Galaxies: Insights from KBSS-MOSFIRE
• First results from SMAUG: Characterization of Multiphase Galactic Outflows from a Suite of Local Star-Forming Galactic Disk Simulations
• Modern yields per stellar generation: the effect of the IMF
• Galaxy Cold Gas Contents in Modern Cosmological Hydrodynamic Simulations
• Revisiting the Integrated Star Formation Law. II. Starbursts and the Combined Global Schmidt Law
• High-redshift major mergers weakly enhance star formation
• The Emission Line Properties of Gravitationally-lensed 1.5 < z < 5 Galaxies
• X-rays across the galaxy population - III. The incidence of AGN as a function of star formation rate
• The ALMA Spectroscopic Survey in the HUDF: CO Excitation and Atomic Carbon in Star-Forming Galaxies at $z=1-3$
• Rotation Curves in z~1-2 Star-Forming Disks: Evidence for Cored Dark Matter Distributions
• A higher efficiency of converting gas to stars push galaxies at z ~ 1.6 well above the star-forming main sequence
• Similar star formation rate and metallicity evolution timescales drive the fundamental metallicity relation
• The Column Density, Kinematics, and Thermal State of Metal-Bearing Gas within the Virial Radius of z~2 Star-Forming Galaxies in the Keck Baryonic Structure Survey
• ALLSMOG: an APEX Low-redshift Legacy Survey for MOlecular Gas. I - molecular gas scaling relations, and the effect of the CO/H2 conversion factor
• The Mass-Metallicity-SFR Relation at z >~ 2 with 3D-HST
• Fundamental metallicity relation in CALIFA, SDSS-IV MaNGA and high-z galaxies
• The CO Luminosity Density at High-z (COLDz) Survey: A Sensitive, Large Area Blind Search for Low-J CO Emission from Cold Gas in the Early Universe with the Karl G. Jansky Very Large Array
• The FMOS-COSMOS survey of star-forming galaxies at $z\sim 1.6$ VI: Redshift and emission-line catalog and basic properties of star-forming galaxies
• Molecular gas content in strongly-lensed z~1.5-3 star-forming galaxies with low IR luminosities
• Molecular Gas in the Lensed Lyman Break Galaxy cB58
• Molecular clouds in the Cosmic Snake normal star-forming galaxy 8 billion years ago
• The MOSDEF survey: AGN multi-wavelength identification, selection biases and host galaxy properties
• The MOSDEF Survey: Dynamical and Baryonic Masses and Kinematic Structures of Star-Forming Galaxies at $1.4\le z\le 2.6$
• A Detailed Study of Gas and Star Formation in a Highly Magnified Lyman Break Galaxy at z=3.07
• The ALMA Spectroscopic Survey in the HUDF: CO emission lines and 3 mm continuum sources
• Evolution of the atomic and molecular gas content of galaxies in dark matter haloes
• The MOSDEF Survey: The First Direct Measurements of the Nebular Dust Attenuation Curve at High Redshift
• The NIRVANDELS Survey: a robust detection of $\alpha$-enhancement in star-forming galaxies at $z\simeq 3.4$
• The MOSDEF-LRIS Survey: The Interplay Between Massive Stars and Ionized Gas in High-Redshift Star-Forming Galaxies
• The MOSDEF survey: a census of AGN-driven ionized outflows at $z=1.4-3.8$
• VLA-ALMA Spectroscopic Survey in the Hubble Ultra Deep Field (VLASPECS): Total Cold Gas Masses and CO Line Ratios for z=2-3 "Main Sequence" Galaxies
• Molecular gas as the driver of fundamental galactic relations
• Galaxy metallicities depend primarily on stellar mass and molecular gas mass
• Total Molecular Gas Masses of z~3 Lyman-Break Galaxies: CO(1-0) Emission in MS1512-cB58 and the Cosmic Eye
• The ALMA Spectroscopic Survey in the Hubble Ultra Deep Field: The nature of the faintest dusty star-forming galaxies
• The ALMA Spectroscopic Survey in the HUDF: Nature and physical properties of gas-mass selected galaxies using MUSE spectroscopy
• The MOSDEF-LRIS Survey: The Connection Between Massive Stars and Ionized Gas in Individual Galaxies at $z\sim 2$
• The MOSDEF Survey: Sulfur Emission-line Ratios Provide New Insights into Evolving ISM Conditions at High Redshift
• The Molecular Gas Reservoirs of $z\sim 2$ Galaxies: A comparison of CO(1-0) and dust-based molecular gas masses
• The role of atomic hydrogen in regulating the scatter of the mass-metallicity relation
• The MOSDEF Survey: Kinematic and Structural Evolution of Star-Forming Galaxies at $1.4\le z\le 3.8$
• The molecular gas content and fuel efficiency of starbursts at z ~ 1.6 with ALMA
• Galaxy And Mass Assembly (GAMA): The connection between metals, specific-SFR, and HI gas in galaxies: the Z-SSFR relation
• Molecular gas properties of a lensed star-forming galaxy at z~3.6: a case study
• A${}^3$COSMOS: A census on the molecular gas mass and extent of main-sequence galaxies across cosmic time
• First results from SMAUG: The need for preventative stellar feedback and improved baryon cycling in semi-analytic models of galaxy formation
• The MOSDEF Survey: A Comprehensive Analysis of the Rest-optical Emission-line Properties of $z\sim 2.3$ Star-forming Galaxies
• The MOSDEF Survey: Implications of the Lack of Evolution in the Dust Attenuation-Mass Relation to z~2
• The mass-metallicity relation at z~1-2 and its dependence on star formation rate
• The evolution of galaxy metallicity scaling relations in cosmological hydrodynamical simulations
• Galaxy downsizing and the redshift evolution of oxygen and nitrogen abundances: origin of the scatter in the N/H-O/H diagram
• The MOSDEF Survey: The Mass-Metallicity relationship and the existence of the FMR at z~1.5
• The First Robust Constraints on the Relationship Between Dust-to-Gas Ratio and Metallicity in Luminous Star-forming Galaxies at High Redshift
• The ALMA Frontier Fields Survey III: 1.1 mm Emission Line Identifications in Abell 2744, MACSJ0416.1-2403, MACSJ1149.5+2223, Abell 370, and Abell S1063
• THE MOSDEF SURVEY: The Nature of Mid-Infrared Excess Galaxies and a Comparison of IR and UV Star Formation Tracers at z~2
• IR SED and Dust Masses of Sub-solar Metallicity Galaxies at z~2.3
• Properties of the Interstellar Medium in Star-Forming Galaxies at z~1.4 revealed with ALMA
• Dust, gas, and metal content in star-forming galaxies at $z\sim 3.3$ revealed with ALMA and Near-IR spectroscopy
• The MOSDEF-LRIS Survey: Connection between Galactic-scale Outflows and the Properties of $z$~2 star-forming Galaxies
• Spatially Resolved Spectroscopy of Sub-mm Galaxies at z~2
• Molecular gas budget and characterization of intermediate-mass star-forming galaxies at $z\approx 2-3$

Cited by in corpus (18)

• A CEERS Discovery of an Accreting Supermassive Black Hole 570 Myr after the Big Bang: Identifying a Progenitor of Massive z > 6 Quasars
• A JWST/NIRSpec Exploration of the Connection between Ionization Parameter, Electron Density, and Star-Formation-Rate Surface Density in z=2.7-6.3 Galaxies
• The gas and stellar content of a metal-poor galaxy at $z=8.496$ as revealed by JWST and ALMA
• A Preview of JWST Metallicity Studies at Cosmic Noon: The First Detection of Auroral [O II] Emission at High Redshift
• The cosmic build-up of dust and metals. Accurate abundances from GRB-selected star-forming galaxies at $1.7<z<6.3$
• The dust-to-gas mass ratio of luminous galaxies as a function of their metallicity at cosmic noon
• Catalogue of model star clusters in the Milky Way and M31 galaxies
• MusE GAs FLOw and Wind (MEGAFLOW) IX. The impact of gas flows on the relations between the mass, star formation rate and metallicity of galaxies
• JWST PRIMER: A deep JWST study of all ALMA-detected galaxies in PRIMER COSMOS -- dust-obscured star-formation history back to z $\simeq$ 7
• Galaxy populations of ProtoClusters in cosmological hydrodynamical simulations
• The JWST EXCELS Survey: gas-phase metallicity evolution at 2 < z < 8
• Ionized Carbon in Galaxies: The [C II] 158 $\mu$m Line as a Total Molecular Gas Mass Tracer Revisited
• Understanding the Universal Dust Attenuation Scaling Relation of Star-Forming Galaxies
• Evolution of cold streams in hot gaseous halos
• A Global Census of Metals in the Universe
• Measuring the gas reservoirs in $10^8<$ M${}_{\star }<10^{11}$ M${}_{\odot }$ galaxies at $1\le z\le 3$
• Molecular gas budget of strongly magnified low-mass star-forming galaxies at cosmic noon
• A ring-shaped starburst as a galactic wind-generating mechanism: Morphology, emission, and mass ejection