Recovering the properties of the interstellar medium through integrated spectroscopy: application to the z~0 ECO volume-limited star-forming galaxy sample

Abstract

Deriving physical parameters from integrated galaxy spectra is paramount to interpret the cosmic evolution of star formation, chemical enrichment, and energetic sources. We develop modeling techniques to characterize the ionized gas properties in the subset of 2052 star-forming galaxies from the volume-limited, dwarf-dominated, z~0 ECO catalog. The MULTIGRIS statistical framework is used to evaluate the performance of various models using strong lines as constraints. The reference model involves physical parameters distributed as power-laws with free parameter boundaries. Specifically, we use combinations of 1D photoionization models (i.e., considering the propagation of radiation toward a single cloud) to match optical HII region lines, in order to provide probability density functions of the inferred parameters. The inference predicts non-uniform physical conditions within galaxies. The integrated spectra of most galaxies are dominated by relatively low-excitation gas with a metallicity around 0.3 solar. Using the average metallicity in galaxies, we provide a new fit to the mass-metallicity relationship which is in line with direct abundance method determinations from the calibrated range at low metallicity to stacks at high metallicity. The average metallicity shows a weakly bimodal distribution which may be due related to external (e.g., refueling of non-cluster early-type galaxies above ~10^9.5 solar masses) or internal processes (more efficient star-formation in metal-rich regions). The specific line set used for inference affects the results and we identify potential issues with the use of the [SII] line doublet. Complex modelling approaches are limited by the inherent 1D model database as well as caveats regarding the gas geometry. Our results highlight, however, the possibility to extract useful and significant information from integrated spectra.

Accepted for publication in A&A (Jan. 24th, 2025)

References in corpus (45)

• Binary Population and Spectral Synthesis Version 2.1: construction, observational verification and new results
• Understanding Galaxy Evolution through Emission Lines
• The Herschel Dwarf Galaxy Survey: I. Properties of the low-metallicity ISM from PACS spectroscopy
• The cold interstellar medium of galaxies in the Local Universe
• Gravitational Quenching in Massive Galaxies and Clusters by Clumpy Accretion
• Fitting AGN/galaxy X-ray-to-radio SEDs with CIGALE and improvement of the code
• Mapping metallicity variations across nearby galaxy disks
• IZI: Inferring the Gas Phase Metallicity (Z) and Ionization Parameter (q) of Ionized Nebulae using Bayesian Statistics
• Modelling the Pan-Spectral Energy Distribution of Starburst Galaxies: II. Control of the \HII Region Parameters
• A Nearby Galaxy Perspective on Dust Evolution. Scaling relations and constraints on the dust build-up in galaxies with the DustPedia and DGS samples
• The Herschel Dwarf Galaxy Survey: II. Physical conditions, origin of [CII] emission, and porosity of the multiphase low-metallicity ISM
• Excitation properties of galaxies with the highest [OIII]/[OII] ratios: No evidence for massive escape of ionizing photons
• The physics of gas phase metallicity gradients in galaxies
• CLEAR: The Gas-Phase Metallicity Gradients of Star-Forming Galaxies at 0.6 < z < 2.6
• Missing Stellar Mass in SED Fitting: Spatially Unresolved Photometry can Underestimate Galaxy Masses
• 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
• A physically-based model of the ionizing radiation from active galaxies for photoionization modeling
• Metallicity gradients in small and nearby spiral galaxies
• The Two-Dimensional Metallicity Distribution and Mixing Scales of Nearby Galaxies
• Sensitivity of PDR Calculations to Microphysical Details
• RAMSES-RTZ: Non-Equilibrium Metal Chemistry and Cooling Coupled to On-The-Fly Radiation Hydrodynamics
• Reconciling escape fractions and observed line emission in Lyman-continuum-leaking galaxies
• Nebular emission from young stellar populations including binary stars
• Inferring the HII region escape fraction of ionizing photons from infrared emission lines in metal-poor star-forming dwarf galaxies
• Gas-phase metallicity profiles of the Bluedisk galaxies: Is metallicity in a local star-formation regulated equilibrium?
• RESOLVE and ECO: Finding Low-Metallicity $z\sim 0$ Dwarf AGN Candidates Using Optimized Emission-Line Diagnostics
• The density structure of supersonic self-gravitating turbulence
• Disentangling the physical parameters of gaseous nebulae and galaxies
• Comparison of Theoretical Starburst Photoionisation Models for Optical Diagnostics
• The BPT Diagram in Cosmological Galaxy Formation Simulations: Understanding the Physics Driving Offsets at High-Redshift
• Correlation between the gas-phase metallicity and ionization parameter in extragalactic HII regions
• Heating of blue compact dwarf galaxies: gas distribution and photoionization by stars in I Zw 18
• The Mid-Infrared [SIV]/[NeII] versus [NeIII]/[NeII] Correlation
• HOMERUN a new approach to photoionization modelling. I -- reproducing observed emission lines with percent accuracy and obtaining accurate physical properties of the ionized gas
• The interplay between feedback, accretion, transport and winds in setting gas-phase metal distribution in galaxies
• Optical and JWST Mid-IR Emission Line Diagnostics for Simultaneous IMBH and Stellar Excitation in z~0 Dwarf Galaxies
• Messenger Monte-Carlo MAPPINGS V (M^3) -- A self-consistent three-dimensional photoionization code
• Emission-line diagnostics of HII regions using conditional Invertible Neural Networks
• Testable predictions of outside-in age gradients in dwarf galaxies of all types
• Neural network-based emulation of interstellar medium models
• Introducing PyCross: PyCloudy Rendering Of Shape Software for pseudo 3D ionisation modelling of nebulae
• Addressing the [O III]/H\b{eta} Offset of Dwarf Galaxies in the RESOLVE Survey
• Identification and Quenching of Nugget Galaxies in the RESOLVE Survey at z = 0
• Probing the heating of the neutral atomic interstellar medium in the Dwarf Galaxy Survey through infrared cooling lines
• Predicting interstellar radiation fields from chemical evolution models

Cited by in corpus (1)

• Emission Line Diagnostics for IMBHs in Dwarf Galaxies: Accounting for BH Seeding and ULX Excitation