The impact of carbon and oxygen abundances on the metal-poor initial mass function

Abstract

Star formation models predict that the metal-poor initial mass function (IMF) can be substantially different from that observed in the metal-rich Milky Way. This changeover occurs because metal-poor gas clouds cool inefficiently due to their lower abundance of metals and dust. However, predictions for the metal-poor IMF to date rely on assuming Solar-scaled abundances, that is, [X/O] = 0 at all [O/H]. There is now growing evidence that elements such as C and O that dominate metal line cooling in the ISM do not follow Solar scaling at low metallicities. In this work, we extend models that predict the variation in the characteristic (or, the peak) IMF mass as a function of metallicity using [C/O] ratios derived from observations of metal-poor Galactic stars and of H II regions in dwarf galaxies. These data show [C/O] < 0 at sub-Solar [O/H], which leads to a substantially different metal-poor IMF in the metallicity range where C I and C II cooling dominate ISM thermodynamics, resulting in an increase in the characteristic mass by a factor as large as 7. An important consequence of this difference is a shift in the location of the transition from a top- to a bottom-heavy IMF upwards by 0.5 $-$ 1 dex in metallicity. Our findings indicate that the IMF is very sensitive to the assumptions around Solar-scaled ISM compositions in metal-poor systems (e.g., dwarf galaxies, the Galactic halo and metal-poor stars) that are a key focus of JWST.

arXiv comment14 pages, 8 figures. Accepted by MNRAS

References in corpus (195)

• SciPy 1.0--Fundamental Algorithms for Scientific Computing in Python
• Array Programming with NumPy
• The chemical composition of the Sun
• Galactic Stellar and Substellar Initial Mass Function
• On the variation of the Initial Mass Function
• The Milky Way in Molecular Clouds: A New Complete CO Survey
• A computer program for fast non-LTE analysis of interstellar line spectra
• An atomic and molecular database for analysis of submillimetre line observations
• A Universal Stellar Initial Mass Function? A Critical Look at Variations
• Starburst-driven Mass Loss from Dwarf Galaxies: Efficiency and Metal Ejection
• Confirmation of the remarkable compactness of massive quiescent galaxies at z~2.3: early-type galaxies did not form in a simple monolithic collapse
• New Interstellar Dust Models Consistent with Extinction, Emission, and Abundance Constraints
• Gas-to-Dust mass ratios in local galaxies over a 2 dex metallicity range
• The GALAH+ Survey: Third Data Release
• Near-Field Cosmology with Metal-Poor Stars
• The Universality of the Stellar IMF
• The Resolved Properties of Extragalactic Giant Molecular Clouds
• A Substantial Population of Low Mass Stars in Luminous Elliptical Galaxies
• Carbon Enhanced Metal-Poor Stars. I. Chemical Compositions of 26 Stars
• Thermal and Fragmentation Properties of Star-forming Clouds in Low-metallicity Environments
• The Stellar Initial Mass Function in Early-Type Galaxies From Absorption Line Spectroscopy. II. Results
• The Atomic to Molecular Transition in Galaxies. II: HI and H_2 Column Densities
• The Formation of the First Low-Mass Stars From Gas With Low Carbon and Oxygen Abundances
• First stars VI - Abundances of C, N, O, Li, and mixing in extremely metal-poor giants. Galactic evolution of the light elements
• Reconciling the Stellar and Nebular Spectra of High Redshift Galaxies
• On the Star Formation Efficiency of Turbulent Magnetized Clouds
• On The Cosmic Origins Of Carbon And Nitrogen
• Physical properties of molecular clouds for the entire Milky Way disk
• An extremely primitive halo star
• Evolution, nucleosynthesis and yields of AGB stars at different metallicities (III): intermediate mass models, revised low mass models and the ph-FRUITY interface
• Protostellar Collapse with Various Metallicities
• Fragmentation of star-forming clouds enriched with the first dust
• Structure and Evolution of the Envelopes of Deeply Embedded Massive Young Stars
• Physical Conditions in a Young, Unreddened, Low Metallicity Galaxy at High Redshift
• The impact of the nitrogen-to-oxygen ratio on ionized nebulae diagnostics based on [NII] emission lines
• High-Resolution Spectroscopy of Extremely Metal-Poor Stars in the Least Evolved Galaxies: Ursa Major II and Coma Berenices
• The Stagger-grid: A Grid of 3D Stellar Atmosphere Models - I. Methods and General Properties
• The first chemical enrichment in the universe and the formation of hyper metal-poor stars
• The Metallicity of Galaxy Disks: Infall versus Outflow
• The dust content of galaxies from z = 0 to z = 9
• Oxygen and Nitrogen in Isolated Dwarf Irregular Galaxies
• HI-to-H2 Transitions and H I Column Densities in Galaxy Star-Forming Regions
• Probing the Formation of the First Low-Mass Stars with Stellar Archaeology
• The Most Metal-Poor Stars. IV. The Two Populations With [Fe/H] < -3.0
• Ultraviolet Emission Lines in Young Low Mass Galaxies at z~2: Physical Properties and Implications for Studies at z>7
• The evolution of the C/O ratio in metal-poor halo stars
• Observational Constraints on First-Star Nucleosynthesis. I. Evidence for Multiple Progenitors of CEMP-no Stars
• 3D Hydrodynamical Simulations of Surface Convection in Red Giant Stars. Impact on spectral line formation and abundance analysis
• Keck HIRES Spectroscopy of Extragalactic HII Regions: C and O Abundances from Recombination Lines
• TOPoS: II. On the bimodality of carbon abundance in CEMP stars. Implications on the early chemical evolution of galaxies
• A cosmic-ray dominated ISM in Ultra Luminous Infrared Galaxies: new initial conditions for star formation
• The Dust-to-Gas and Dust-to-Metals Ratio in Galaxies from z=0-6
• Tracing the total molecular gas in galaxies: [CII] and the CO-dark gas
• On the abundance discrepancy problem in HII regions
• The Atomic-to-Molecular Transition in Galaxies. III. A New Method for Determining the Molecular Content of Primordial and Dusty Clouds
• Carbon and Oxygen Abundances in Low Metallicity Dwarf Galaxies
• The Evolution of C/O in Dwarf Galaxies from HST Fos Observations
• Evolution and nucleosynthesis of asymptotic giant branch stellar models of low metallicity
• HE 1327-2326, an unevolved star with [Fe/H]<-5.0. II. New 3D-1D corrected abundances from a VLT/UVES spectrum
• Sulphur and zinc abundances in Galactic halo stars revisited
• Carbon, oxygen, and iron abundances in disk and halo stars. Implications of 3D non-LTE spectral line formation
• The localized chemical pollution in NGC 5253 revisited: Results from deep echelle spectrophotometry
• SLUG -- Stochastically Lighting Up Galaxies. III: A Suite of Tools for Simulated Photometry, Spectroscopy, and Bayesian Inference with Stochastic Stellar Populations
• The Chemical Evolution of Carbon, Nitrogen, and Oxygen in Metal-Poor Dwarf Galaxies
• JINAbase: A database for chemical abundances of metal-poor stars
• Carbon and oxygen abundances in stellar populations
• Metal-enriched galactic outflows shape the mass-metallicity relationship
• A Window On The Earliest Star Formation: Extreme Photoionization Conditions of a High-Ionization, Low-Metallicity Lensed Galaxy at z~2
• Variations of the stellar initial mass function in the progenitors of massive early-type galaxies and in extreme starburst environments
• The Dawes Review 8: Measuring the Stellar Initial Mass Function
• Star formation in metal-poor gas clouds
• Non-LTE oxygen line formation in 3D hydrodynamic model stellar atmospheres
• Gravitationally Lensed Galaxies at 2<z<3.5: Direct Abundance Measurements of Lya Emitters
• Abundance scaling in stars, nebulae and galaxies
• Radiation-Hydrodynamic Simulations of the Formation of Orion-Like Star Clusters I. Implications for the Origin of the Initial Mass Function
• The Origin of Carbon-Enhancement and Initial Mass Function of Extremely Metal-Poor Stars in the Galactic Halo
• The first low-mass stars: critical metallicity or dust-to-gas ratio?
• A First Look at the Abundance Pattern -- O/H, C/O, and Ne/O -- in $z>7$ Galaxies with JWST/NIRSpec
• Carbon in Spiral Galaxies from Hubble Space Telescope Spectroscopy
• The Stellar Abundances for Galactic Archaeology (SAGA) Database II - Implications for Mixing and Nucleosynthesis in Extremely Metal-Poor Stars and Chemical Enrichment of the Galaxy
• Carbon and oxygen abundances from recombination lines in low-metallicity star-forming galaxies. Implications for chemical evolution
• High-resolution spectroscopy of a young, low-metallicity optically-thin L=0.02L* star-forming galaxy at z=3.12
• Galactic Evolution of Nitrogen
• The role of binaries in the enrichment of the early Galactic halo. II. Carbon-Enhanced Metal-Poor Stars - CEMP-no stars
• Low-Metallicity Star Formation : Prestellar Collapse and Protostellar Accretion in the Spherical Symmetry
• Dynamical Mass Estimates for Two Luminous Star Clusters in Galactic Merger Remnants
• The statistical properties of stars and their dependence on metallicity
• Zn and Cr abundances in damped Lyman alpha systems from the CORALS survey
• Carbon Nitrogen, and Oxygen Galactic Gradients: A Solution to the Carbon Enrichment Problem
• The chemical compositions of the extreme halo stars HE0107-5240 and HE1327-2326 inferred from 3D hydrodynamical model atmospheres
• High-precision stellar abundances of the elements - methods and applications
• The statistical properties of stars and their dependence on metallicity: the effects of opacity
• The oxygen abundance calibrations and N/O abundance ratios of ~40,000 SDSS star-forming galaxies
• The C/O ratio at low metallicity: constraints on early chemical evolution from observations of Galactic halo stars
• The evolution of CNO isotopes: the impact of massive stellar rotators
• Theoretical ISM pressure and electron density diagnostics for local and high-redshift galaxies
• The Physical Conditions, Metallicity and Metal Abundance Ratios In a Highly Magnified Galaxy at z = 3.6252
• Galaxy And Mass Assembly (GAMA): A forensic SED reconstruction of the cosmic star formation history and metallicity evolution by galaxy type
• Is atomic carbon a good tracer of molecular gas in metal-poor galaxies?
• On the O/H, Mg/H, Si/H and Fe/H Gas and Dust Abundance Ratios in Galactic and Extragalactic H II Regions
• Carbon and oxygen in HII regions of the Magellanic Clouds: abundance discrepancy and chemical evolution
• Detailed dust modelling in the L-Galaxies semi-analytic model of galaxy formation
• Physical Properties of Molecular Clouds at 2 parsec Resolution in the Low-Metallicity Dwarf Galaxy NGC 6822 and the Milky Way
• DESPOTIC -- A New Software Library to Derive the Energetics and SPectra of Optically Thick Interstellar Clouds
• Dense cloud cores revealed by CO in the low metallicity dwarf galaxy WLM
• Understanding star formation in molecular clouds II. Signatures of gravitational collapse of IRDCs
• Metals, dust and the cosmic microwave background: fragmentation of high-redshift star-forming clouds
• On the Origin of Stellar Masses
• First Insights into the ISM at $z>8$ with JWST: Possible Physical Implications of a High [O III]$\lambda 4363$/[O III]$\lambda 5007$
• HD and H2 formation in low-metallicity dusty gas clouds at high redshift
• Temperature and Metallicity Gradients in the Hot Gas Outflows of M82
• Testing metallicity indicators at z~1.4 with the gravitationally lensed galaxy CASSOWARY 20
• The lowest detected stellar Fe abundance: The halo star SMSS J160540.18-144323.1
• CLASSY IV: Exploring UV diagnostics of the interstellar medium in local high-$z$ analogs at the dawn of the JWST era
• The Physical Conditions in a Pre Super Star Cluster Molecular Cloud in the Antennae Galaxies
• Inelastic O+H collisions and the OI 777nm solar centre-to-limb variation
• Binarity among CEMP-no stars: an indication of multiple formation pathways?
• High-resolution spectroscopy of extremely metal-poor stars in the least evolved galaxies: Bootes II
• The physics of gas phase metallicity gradients in galaxies
• CO/H2, C/CO, OH/CO, and OH/O2 in Dense Interstellar Gas: From High Ionization to Low Metallicity
• Dust scaling relations in a cosmological simulation
• The most metal-poor damped Lyman alpha systems: An insight into dwarf galaxies at high redshift
• Evidence for an aspherical Population III supernova explosion inferred from the hyper metal-poor star HE1327-2326
• Carbon-enhanced metal-poor stars: a window on AGB nucleosynthesis and binary evolution. I. Detailed analysis of 15 binary stars with known orbital periods
• Beryllium and Alpha-Element Abundances in a Large Sample of Metal-Poor Stars
• The chemical evolution of the Bootes I ultra-faint dwarf galaxy
• The Pristine survey VIII: The metallicity distribution function of the Milky Way halo down to the extremely metal-poor regime
• Evidence of a non universal stellar Initial Mass Function. Insights from HST optical imaging of 6 Ultra Faint Dwarf Milky Way Satellites
• Metallicity dependence of the H/H${}_2$ and C${}^{+}$/C/CO distributions in a resolved self-regulating interstellar medium
• The origin of dust in galaxies across cosmic time
• Impact of the cosmic background radiation on the initial mass function of metal-poor stars
• Oxygen abundances in metal-poor subgiants as determined from [O I], O I and OH lines
• Seeding the Second Star: enrichment from population III, dust evolution, and cloud collapse
• The Necessity of Feedback Physics in Setting the Peak of the Initial Mass Function
• Zero-metallicity hypernova uncovered by an ultra metal-poor star in the Sculptor dwarf spheroidal galaxy
• Stellar and nebular diagnostics in the UV for star-forming galaxies
• The Pristine Inner Galaxy Survey (PIGS) II: Uncovering the most metal-poor populations in the inner Milky Way
• Chemical Abundance Signature of J0023+0307 -- A Second-Generation Main-Sequence Star with [Fe/H]<-6
• 3D non-LTE line formation of neutral carbon in the Sun
• BACCHUS Analysis of Weak Lines in APOGEE Spectra (BAWLAS)
• Ultra-faint dwarf galaxies: unveiling the minimum mass of the first stars
• Carbon and oxygen in metal-poor halo stars
• Carbon monoxide in an extremely metal-poor galaxy
• Chemical consequences of low star formation rates: stochastically sampling the IMF
• What Physics Determines the Peak of the IMF? Insights from the Structure of Cores in Radiation-Magnetohydrodynamic Simulations
• Magnetic field amplification in accretion discs around the first stars: implications for the primordial IMF
• Discovery of the most metal-poor damped Lyman-alpha system
• First stars in Damped Lyman Alpha systems
• Metallicity, ionization parameter, and pressure variations of HII regions in the TYPHOON spiral galaxies
• Supernova dust formation and the grain growth in the early universe: The critical metallicity for low-mass star formation
• First Results from the $Herschel$ and ALMA Spectroscopic Surveys of the SMC: The Relationship Between [CII]-bright Gas and CO-bright Gas at Low Metallicity
• The origin of carbon: Low-mass stars and an evolving, initially top-heavy IMF?
• Gravitational collapse and the thermal evolution of low-metallicity gas clouds in the early Universe
• Chemical Abundance Analysis of Three $\alpha$-Poor, Metal-Poor Stars in the Ultra-Faint Dwarf Galaxy Horologium I
• Metallicity and the Universality of the IMF
• Metal Mixing and Ejection in Dwarf Galaxies is Dependent on Nucleosynthetic Source
• Far-Infrared Spectral Energy Distributions of Embedded Protostars and Dusty Galaxies: I. Theory for Spherical Sources
• Transition of the Stellar Initial Mass Function Explored with Binary Population Synthesis
• On the origin of the mass-metallicity gradient relation in the local Universe
• The Most Metal-Poor Stars. V. The CEMP-no Stars in 3D and Non-LTE
• Detection of a population of carbon-enhanced metal-poor stars in the Sculptor dwarf spheroidal galaxy
• Characterizing the transition from diffuse atomic to dense molecular clouds in the Magellanic clouds with [CII], [CI], and CO
• The Magellan Evolution of Galaxies Spectroscopic and Ultraviolet Reference Atlas (MEGaSaURA) II: Stacked Spectra
• On the variation of carbon abundance in galaxies and its implications
• Combining radiative transfer and diffuse interstellar medium physics to model star formation
• The DUVET Survey: Direct $T_e$-based metallicity mapping of metal-enriched outflows and metal-poor inflows in Mrk 1486
• High resolution spectroscopic follow-up of the most metal-poor candidates from SkyMapper DR1.1
• Origin of the CEMP-no Group Morphology in the Milky Way
• The MASSIVE SURVEY XVI. The Stellar Initial Mass Function in the Center of MASSIVE Early-Type Galaxies
• An in-depth spectroscopic examination of molecular bands from 3D hydrodynamical model atmospheres I. Formation of the G-band in metal-poor dwarf stars
• New Insights into the Physical Conditions and Internal Structure of a Candidate Proto-Globular Cluster
• Galactic Evolution of Oxygen: OH lines in 3D hydrodynamical model atmospheres
• The chemical abundance pattern of the extremely metal-poor thin disk star 2MASS J1808-5104 and its origins
• An in-depth spectroscopic examination of molecular bands from 3D hydrodynamical model atmospheres. II. Carbon-enhanced metal-poor 3D model atmospheres
• Chemical Evolution of Dwarf Irregular and Blue Compact Galaxies
• Thermal Pressures in the Interstellar Medium of the Magellanic Clouds
• The Molecular Clouds Fueling a 1/5 Solar Metallicity Starburst
• Stromlo Stellar Tracks: non-solar scaled abundances for massive stars
• High-resolution three-dimensional simulations of gas removal from ultrafaint dwarf galaxies. I. Stellar feedback
• On the origin of nitrogen at low metallicity
• First extragalactic measurement of the turbulence driving parameter: ALMA observations of the star-forming region N159E in the Large Magellanic Cloud
• The chemical signature of surviving Population III stars in the Milky Way
• The role of the H${}_2$ adiabatic index in the formation of the first stars
• Origins of carbon-enhanced metal-poor stars
• Fragmentation in Dusty Low-Metallicity Star Forming Halos
• The influence of a top-heavy integrated galactic IMF and dust on the chemical evolution of high-redshift starbursts
• HI-to-H${}_2$ Transitions in Dust-Free Interstellar Gas
• Do the environmental conditions affect the dust-induced fragmentation in low-metallicity clouds ?: Effect of pre-ionization and far-ultraviolet/cosmic-ray fields
• Chemical abundance analysis of extremely metal-poor stars in the Sextans dwarf spheroidal galaxy
• Chemical evolution of ultra-faint dwarf galaxies: testing the IGIMF
• The metallic winds in dwarf galaxies
• Implications of a non-universal IMF from C, N, and O abundances in very metal-poor Galactic stars and damped Lyman-alpha absorbers
• The Pressure of the Star Forming ISM in Cosmological Simulations
• Photometric Redshifts of Submillimeter Galaxies
• The effect of metallicity on the abundances of molecules in protoplanetary disks

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• Population III star formation in the presence of turbulence, magnetic fields and ionizing radiation feedback
• Fluorine abundances in CEMP stars at the lowest metallicity: Hints on the nature of the first stars
• SILCC -- IX. The multi-phase interstellar medium at low metallicity