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

Abstract

We conduct a statistical analysis of the factors responsible for the variation in the ionization parameter (U) of high-redshift star-forming galaxies based on medium resolution JWST/NIRSpec observations obtained by the Cosmic Evolution Early Release Science (CEERS) survey. The sample consists of 48 galaxies with spectroscopic redshifts z=2.7-6.3 which are largely representative of typical star-forming galaxies at these redshifts. The [SII] 6718, 6733 doublet is used to estimate electron densities (n_e), and dust-corrected Ha luminosities are used to compute total ionizing photon rates (Q). Using composite spectra of galaxies in bins of [OIII]/[OII] (i.e., O32) as a proxy for U, we determine that galaxies with higher O32 have <n_e> ~ 500 cm^-3 that are at least a factor of ~5 larger than that of lower-O32 galaxies. We do not find a significant difference in <Q> between low- and high-O32 galaxies. Photoionization modeling of all available strong rest-frame optical emission lines is used to simultaneously constrain U and oxygen abundance (Z_neb). We find a large spread in log U of ~1.5 dex at a fixed Z_neb. On the other hand, the data indicate a highly significant correlation between U and star-formation-rate surface density (Sigma_SFR) which appears to be redshift invariant at z~1.6-6.3, and possibly up to z~9.5. We consider several avenues through which metallicity and Sigma_SFR (or gas density) may influence U, including variations in n_e and Q that are tied to metallicity and gas density, internal dust extinction of ionizing photons, and the effects of gas density on the volume filling fraction of dense clumps in HII regions and the escape fraction of ionizing photons. Based on these considerations, we conclude that gas density may play a more central role than metallicity in modulating U at these redshifts.

arXiv comment16 pages, 13 figures, 4 tables

References in corpus (103)

• Galactic Stellar and Substellar Initial Mass Function
• The Dust Content and Opacity of Actively Star-Forming Galaxies
• The Global Schmidt Law in Star Forming Galaxies
• 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
• Mass-loss predictions for O and B stars as a function of metallicity
• Multiwavelength study of massive galaxies at z~2. I. Star formation and galaxy growth
• A Quantitative Comparison of SMC, LMC, and Milky Way UV to NIR Extinction Curves
• Dust Masses, PAH Abundances, and Starlight Intensities in the SINGS Galaxy Sample
• An ultra-deep near-infrared spectrum of a compact quiescent galaxy at z=2.2
• Pre-Supernova Evolution of Massive Single and Binary Stars
• Binary Population and Spectral Synthesis Version 2.1: construction, observational verification and new results
• Rotating Massive Main-Sequence Stars I: Grids of Evolutionary Models and Isochrones
• Gas-to-Dust mass ratios in local galaxies over a 2 dex metallicity range
• Reevaluating Old Stellar Populations
• New Constraints on Cosmic Reionization from the 2012 Hubble Ultra Deep Field Campaign
• CEERS Key Paper I: An Early Look into the First 500 Myr of Galaxy Formation with JWST
• The Effects of Stellar Rotation. II. A Comprehensive Set of Starburst99 Models
• Reconciling the Stellar and Nebular Spectra of High Redshift Galaxies
• Gas metallicity diagnostics in star-forming galaxies
• Dust Obscuration and Metallicity at High Redshift: New Inferences from UV, H-alpha, and 8 Micron Observations of z~2 Star-Forming Galaxies
• Ionization State of Inter-Stellar Medium in Galaxies: Evolution, SFR-M_star-Z Dependence, and Ionizing Photon Escape
• Star Formation and Extinction in Redshift z~2 Galaxies: Inferences from Spitzer MIPS Observations
• The Keck Lyman Continuum Spectroscopic Survey (KLCS): The Emergent Ionizing Spectrum of Galaxies at $z\sim 3$
• 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
• The Dynamics of Radiation Pressure-Dominated HII Regions
• Escape of Ionizing Radiation from High Redshift 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
• Modelling the Pan-Spectral Energy Distribution of Starburst Galaxies: IV The Controlling Parameters of the Starburst SED
• Metallicity evolution, metallicity gradients and gas fractions at z~3.4
• Strongly star forming galaxies in the local Universe with nebular He II 4686 emission
• New insights into the stellar content and physical conditions of star-forming galaxies at z = 2-3 from spectral modelling
• Fluctuating feedback-regulated escape fraction of ionizing radiation in low-mass, high-redshift galaxies
• The HDUV Survey: A Revised Assessment of the Relationship between UV Slope and Dust Attenuation for High-Redshift Galaxies
• Deriving model-based T${}_e$-consistent chemical abundances in ionised gaseous nebulae
• On Radiation Pressure in Static, Dusty HII Regions
• The Lyman-Continuum Photon Production Efficiency xi_{ion} of z~4-5 Galaxies from IRAC-based Halpha Measurements: Implications for the Escape Fraction and Cosmic Reionization
• GOODS-HERSCHEL: star formation, dust attenuation and the FIR-radio correlation on the Main Sequence of star-forming galaxies up to z~4
• GOODS-Herschel:dust attenuation properties of UV selected high redshift galaxies
• Metallicities and Physical Conditions in Star-forming Galaxies at z~1.0-1.5
• Ultraviolet spectra of extreme nearby star-forming regions --- approaching a local reference sample for JWST
• The MOSDEF Survey: Direct-Method Metallicities and ISM Conditions at $z\sim 1.5-3.5$
• Geometry of Star-Forming Galaxies from SDSS, 3D-HST and CANDELS
• The Nature of Starburst Activity in M82
• The Rising Star-Formation Histories of Distant Galaxies and Implications for Gas Accretion with Time
• Near-infrared Integral Field Spectroscopy and Mid-infrared Spectroscopy of the Starburst Galaxy M82
• Binary Stars Can Provide the "Missing Photons" Needed for Reionization
• The MOSDEF Survey: Direct Observational Constraints on the Ionizing Photon Production Efficiency, ${\xi }_{\mathrm{ion}}$, at z~2
• Modelling the Pan-Spectral Energy Distribution of Starburst Galaxies: II. Control of the \HII Region Parameters
• Radio Continuum and Recombination Line Study of UC HII Regions with Extended Envelopes
• No missing photons for reionization: moderate ionizing photon escape fractions from the FIRE-2 simulations
• Measuring the Physical Conditions in High-Redshift Star-Forming Galaxies: Insights from KBSS-MOSFIRE
• The Connection Between Reddening, Gas Covering Fraction, and the Escape of Ionizing Radiation at High Redshift
• Revisiting the Integrated Star Formation Law. II. Starbursts and the Combined Global Schmidt Law
• X-ray binaries as the origin of nebular HeII emission in low-metallicity star-forming galaxies
• First Spectroscopic Evidence for High Ionization State and Low Oxygen Abundance in Lya Emitters
• The MOSDEF Survey: the Variation of the Dust Attenuation Curve with Metallicity
• Theory and Diagnostics of Hot Star Mass Loss
• The VANDELS survey: the stellar metallicities of star-forming galaxies at 2.5 < z < 5.0
• Understanding the escape of LyC and Ly$\alpha$ photons from turbulent clouds
• Lyman Radiation Hydrodynamics of Turbulent H II Regions in Molecular Clouds: A Physical Origin of LyC Leakage and the Associated Ly$\alpha$ Spectra
• Neutral gas properties of Lyman continuum emitting galaxies: column densities and covering fractions from UV absorption lines
• A Magnified Compact Galaxy at Redshift 9.51 with Strong Nebular Emission Lines
• Neon and Argon optical emission lines in ionized gaseous nebulae: Implications and applications
• The COSMOS [OII] Survey: Evolution of Electron Density with Star Formation Rate
• The MOSDEF Survey: The First Direct Measurements of the Nebular Dust Attenuation Curve at High Redshift
• SDSS-IV MaNGA: What Shapes The Distribution Of Metals In Galaxies? Exploring The Roles Of The Local Gas Fraction And Escape Velocity
• Stars were born in significantly denser regions in the early Universe
• Dust Attenuation, Star Formation, and Metallicity in z ~ 2-3 Galaxies from KBSS-MOSFIRE
• On the importance of using appropriate spectral models to derive physical properties of galaxies at 0.7<z<2.8
• The MOSDEF-LRIS Survey: The Interplay Between Massive Stars and Ionized Gas in High-Redshift Star-Forming Galaxies
• The NIRVANDELS Survey: a robust detection of $\alpha$-enhancement in star-forming galaxies at $z\simeq 3.4$
• A Tight Relation Between N/O Ratio and Galaxy Stellar Mass Can Explain the Evolution of Strong Emission Line Ratios with Redshift
• The size--density relation of extragalactic HII regions
• The Effects of Stellar Population and Gas Covering Fraction on the Emergent Lyman Alpha Emission of High-Redshift Galaxies
• Lyman Continuum Extinction by Dust in H {\sc ii} Regions of Galaxies
• Investigating H$\alpha$, UV, and IR star-formation rate diagnostics for a large sample of z ~ 2 galaxies
• Ionization Parameter as a Diagnostic of Radiation and Wind Pressures in H II Regions and Starburst Galaxies
• [NeIII]/[OII] as an Ionization Parameter Diagnostic in Star-Forming Galaxies
• The MOSDEF-LRIS Survey: The Connection Between Massive Stars and Ionized Gas in Individual Galaxies at $z\sim 2$
• Initial Mass Function Variations Cannot Explain the Ionizing Spectrum of Low Metallicity Starbursts
• Exploring HeII$\lambda$1640 emission line properties at $z\sim 2-4$
• The MOSDEF Survey: The strong agreement between H-alpha and UV-to-FIR star formation rates for z~2 star-forming galaxies
• The metallicity's fundamental dependence on both local and global galactic quantities
• Local Analogs for High-redshift Galaxies: Resembling the Physical Conditions of the Interstellar Medium in High-redshift Galaxies
• Paschen-line Constraints on Dust Attenuation and Star Formation at z~1-3 with JWST/NIRSpec
• The KMOS${}^{3D}$ Survey: Investigating the Origin of the Elevated Electron Densities in Star-Forming Galaxies at $1\lesssim z\lesssim 3$
• The MOSDEF Survey: A Comprehensive Analysis of the Rest-optical Emission-line Properties of $z\sim 2.3$ Star-forming Galaxies
• JWST/NIRSpec Measurements of the Relationships Between Nebular Emission-line Ratios and Stellar Mass at z~3-6
• The ionisation parameter of star-forming galaxies evolves with the specific star formation rate
• Effects of photon escape on diagnostic diagrams for HII regions
• The Impact of Star-Formation-Rate Surface Density on the Electron Density and Ionization Parameter of High-Redshift Galaxies
• Disentangling the physical parameters of gaseous nebulae and galaxies
• The growth of H II regions around massive stars: the role of metallicity and dust
• CO Emission, Molecular Gas, and Metallicity in Main-Sequence Star-Forming Galaxies at $z\sim 2.3$
• The MOSDEF Survey: Neon as a Probe of ISM Physical Conditions at High Redshift
• Physics of Prodigious Lyman Continuum Leakers
• The Ionizing Spectra of Extremely Metal-Poor O Stars: Constraints from the Only HII Region in Leo P
• The filling factor - radius relation for 58 HII regions across the disk of NGC6946
• Correlation between SFR surface density and thermal pressure of ionized gas in local analogs of high-redshift galaxies
• Dust attenuation of the nebular regions and optical emission lines of $z\sim 2$ star-forming galaxies
• Lyman-Alpha Escape from Low-Mass, Compact, High-Redshift Galaxies
• The Direct-Method Oxygen Abundance of Typical Dwarf Galaxies at Cosmic High-Noon

Cited by in corpus (32)

• JADES: Detecting [OIII]$\lambda 4363$ Emitters and Testing Strong Line Calibrations in the High-$z$ Universe with Ultra-deep JWST/NIRSpec Spectroscopy up to $z\sim 9.5$
• JADES: Carbon enrichment 350 Myr after the Big Bang in a gas-rich galaxy
• A luminous and young galaxy at z=12.33 revealed by a JWST/MIRI detection of Hα and [OIII]
• The UNCOVER Survey: A First-look HST+JWST Catalog of Galaxy Redshifts and Stellar Population Properties Spanning $0.2\lesssim z\lesssim 15$
• JADES: The star-formation and chemical enrichment history of a luminous galaxy at z~9.43 probed by ultra-deep JWST/NIRSpec spectroscopy
• Dust attenuation evolution in $z\sim 2$-$12$ JWST galaxies
• Ionized gas kinematics and chemical abundances of low-mass star-forming galaxies at $z\sim 3$
• GA-NIFS: Multi-phase analysis of a star-forming galaxy at $z\sim 5.5$
• The evolution of the SFR and Sigma-SFR of galaxies in cosmic morning (4 < z < 10)
• Anatomy of a z=6 Lyman-α emitter down to parsec scales: extreme UV slopes, metal-poor regions and possibly leaking star clusters
• A quasar-galaxy merger at $z\sim 6.2$: rapid host growth via accretion of two massive satellite galaxies
• GA-NIFS: JWST/NIRSpec IFS view of the z~3.5 galaxy GS5001 and its close environment at the core of a large-scale overdensity
• The density-bounded twilight of starbursts in the early Universe
• Extreme Ionizing Properties of Metal-Poor, Muv ~ -12 Star Complex in the first Gyr
• Early Results from GLASS-JWST. XXV. Electron Density in the Interstellar Medium at $0.7\lesssim z\lesssim 9.3$ with NIRSpec High-resolution Spectroscopy
• The GLASS-JWST Early Release Science Program. IV. Data release of 263 spectra from 245 unique sources
• Evolution of the UV slope of galaxies at cosmic morning (z > 4): the properties of extremely blue galaxies
• Feedback and dynamical masses in high-$z$ galaxies: the advent of high-resolution NIRSpec spectroscopy
• Exploring Spatially-Resolved Metallicities, Dynamics and Outflows in Low-Mass Galaxies at $z\sim 7.6$
• Detection of the 2175Å UV Bump at z>7: Evidence for Rapid Dust Evolution in a Merging Reionisation-Era Galaxy
• NGDEEP: The Star Formation and Ionization Properties of Galaxies at $1.7<z<3.4$
• The JWST Emission Line Survey (JELS): Extending rest-optical narrow-band emission line selection into the Epoch of Reionization
• Physical properties of strong 1 < z < 3 Balmer and Paschen lines emitters observed with JWST
• Insights on Metal Enrichment and Environmental Effect at $z\approx 5-7$ with JWST ASPIRE/EIGER and Chemical Evolution Model
• The JWST/AURORA Survey: Multiple Balmer and Paschen Emission Lines for Individual Star-forming Galaxies at z=1.5-4.4. I. A Diversity of Nebular Attenuation Curves and Evidence for Non-Unity Dust Covering Fractions
• Cloudy-Maraston: Integrating nebular continuum and line emission with the Maraston stellar population synthesis models
• The Cliff: A Metal-Poor Little Red Dot Hosting an Overmassive Black Hole at $z=3.55$
• Reionization in Protocluster Environments at $z>7$ with JWST/NIRSpec
• Recovering the properties of the interstellar medium through integrated spectroscopy: application to the z~0 ECO volume-limited star-forming galaxy sample
• Unraveling the Lyman Continuum Emission of Ion3: Insights from HST multi-band imaging and X-Shooter spectroscopy
• The ALMA View of High-Redshift Galaxy Formation
• The Cosmic Rush Hour: Rapid Formation of Bright, Massive, Disky, Star-Forming Galaxies as Signatures of Early-Universe Physics