Topological models to infer multiphase interstellar medium properties

Abstract

(abridged) Spectroscopic observations of high-redshift galaxies slowly reveal the same complexity of the interstellar medium (ISM) as expected from resolved observations in nearby galaxies. While providing a wealth of diagnostics, such high-z spectra are often unresolved, and inferring reliable diagnostics represents a major obstacle. Bright, nearby, unresolved galaxies provide many constraints to design methods to infer ISM properties, but they have so far been limited to deterministic methods and/or with simple topological assumptions. Multicomponent ISM models associate a complex enough distribution of matter and phases with a simple enough topological description to be constrained with probabilistic frameworks. Our goal is to provide a flexible statistical framework that is agnostic to the model grid and that considers either a few discrete components defined by their parameter values and/or statistical distributions of parameters. In this study we present a the MULTIGRIS framework and use it to model a suite of spectral lines in the star-forming regions of the metal-poor dwarf galaxy IZw18. We are able to calculate accurate values for the metallicity, number of ionizing photons, masses of ionized and neutral hydrogen, as well as the dust mass and the dust-to-gas mass ratio. We find a relatively modest amount of H${}_2$ which is predominantly CO-dark and traced by C${}^{+}$ rather than C${}^0$. Nevertheless, more than $90$% of the [CII] emission is associated with the neutral atomic gas. Our models confirm the necessity to consider an X-ray source. Finally, we investigate the escape fraction of ionizing photons for different energy ranges. While the escape fraction for the main HII region lies around $50-65$%, we show that most of the soft X-ray photons are able to escape and may play a role in the ionization and heating of the circumgalactic or intergalactic medium.

arXiv commentAccepted for publication in A&A

References in corpus (53)

• Practical Bayesian model evaluation using leave-one-out cross-validation and WAIC
• Herschel Space Observatory - An ESA facility for far-infrared and submillimetre astronomy
• The Spitzer Space Telescope Mission
• The Photodetector Array Camera and Spectrometer (PACS) on the Herschel Space Observatory
• The CO-to-H2 Conversion Factor
• Rank-normalization, folding, and localization: An improved $\hat{R}$ for assessing convergence of MCMC
• The Infrared Spectrograph on the Spitzer Space Telescope
• CIGALE: a python Code Investigating GALaxy Emission
• A simple model to interpret the ultraviolet, optical and infrared emission from galaxies
• Binary Population and Spectral Synthesis Version 2.1: construction, observational verification and new results
• The CO-to-H2 Conversion Factor and Dust-to-Gas Ratio on Kiloparsec Scales in Nearby Galaxies
• Star Formation and Dust Attenuation Properties in Galaxies from a Statistical UV-to-FIR Analysis
• Understanding Galaxy Evolution through Emission Lines
• Fitting the integrated Spectral Energy Distributions of Galaxies
• Low CO Luminosities in Dwarf Galaxies
• An Overview of the Dwarf Galaxy Survey
• Stellar black holes at the dawn of the universe
• Helium abundance in the most metal-deficient blue compact galaxies: I Zw 18 and SBS 0335-052
• The Spitzer Survey of the Small Magellanic Cloud: FIR Emission and Cold Gas in the SMC
• The dusty MOCASSIN: fully self-consistent 3D photoionisation and dust radiative transfer models
• Large Population of ALMA Galaxies at z>6 with Very High [OIII]88um to [CII]158um Flux Ratios: Evidence of Extremely High Ionization Parameter or PDR Deficit?
• Tracing the total molecular gas in galaxies: [CII] and the CO-dark gas
• Linking dust emission to fundamental properties in galaxies: The low-metallicity picture
• I Zw 18 revisited with HST/ACS and Cepheids: New Distance and Age
• SILVERRUSH. V. Census of Lya, [OIII]5007, Ha, and [CII]158um Line Emission with ~1000 LAEs at z=4.9-7.0 Revealed with Subaru/HSC
• 3D-PDR: A new three-dimensional astrochemistry code for treating Photodissociation Regions
• 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
• Molecular gas in low-metallicity starburst galaxies: Scaling relations and the CO-to-H${}_2$ conversion factor
• The nature of the interstellar medium of the starburst low-metallicity galaxy Haro11: a multi-phase model of the infrared emission
• BOND: Bayesian Oxygen and Nitrogen abundance Determinations in giant H II regions using strong and semi-strong lines
• The Panchromatic Hubble Andromeda Treasury XV. The BEAST: Bayesian Extinction and Stellar Tool
• Chandra Observations of the Three Most Metal-Deficient Blue Compact Dwarf Galaxies known in the Local Universe, SBS 0335-052, SBS 0335-052W, and I Zw 18
• Interpreting the Ionization Sequence in AGN Emission-Line Spectra
• Exploring the Overabundance of ULXs in Metal- and Dust-poor Local Lyman Break Analogs
• The mass-metallicity relation of local active galaxies
• Neutral gas heating by X-rays in primitive galaxies: Infrared observations of IZw18 with Herschel
• TORUS-3DPDR: A self-consistent code treating three-dimensional photoionization and photodissociation regions
• Galaxy evolution studies with the SPace IR telescope for Cosmology and Astrophysics (SPICA): the power of IR spectroscopy
• Inferring the HII region escape fraction of ionizing photons from infrared emission lines in metal-poor star-forming dwarf galaxies
• X-ray Binary Luminosity Function Scaling Relations in Elliptical Galaxies: Evidence for Globular Cluster Seeding of Low-Mass X-ray Binaries in Galactic Fields
• Modeling ionized gas in low-metallicity environments: the Local Group dwarf galaxy IC10
• Heating of blue compact dwarf galaxies: gas distribution and photoionization by stars in I Zw 18
• The Escape Fraction of Ionizing Radiation from Galaxies
• Interpreting the Ionization Sequence in Star-Forming Galaxy Emission-Line Spectra
• A State Transition of the Luminous X-ray Binary in the Low-Metallicity Blue Compact Dwarf Galaxy I Zw 18
• 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
• First [NII]122$\mu$m line detection in a QSO-SMG pair BRI 1202-0725 at $z=4.69$
• Dense and warm neutral gas in BR1202-0725 at z = 4.7 as traced by the [O I] 145 um line
• Extremely weak CO emission in IZw 18
• Observations of [OI]63micron line emission in main-sequence galaxies at z~1.5
• Disentangling emission from star-forming regions in the Magellanic Clouds: Linking [OIII]88 micron and 24 micron

Cited by in corpus (1)

• Dissecting the Mid-Infrared Heart of M83 with JWST