Inferring the HII region escape fraction of ionizing photons from infrared emission lines in metal-poor star-forming dwarf galaxies

Autor: L. Ramambason, V. Lebouteiller, A. Bik, C. T. Richardson, F. Galliano, D. Schaerer, C. Morisset, F. L. Polles, S. C. Madden, M. Chevance, I. De Looze
Přispěvatelé: Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Elon University [NC, USA], SOFIA/USRA, Moffett Field, CA 94035, USA, Département d'Astrophysique (ex SAP) (DAP), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay
Jazyk: angličtina
Rok vydání: 2022
Předmět:
[PHYS.ASTR.HE]Physics [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE]
[PHYS.ASTR.IM]Physics [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM]
H II REGIONS
dwarf [galaxies]
MU-M
FOS: Physical sciences
LYMAN CONTINUUM ESCAPE
Astrophysics::Cosmology and Extragalactic Astrophysics
CHEMICAL-COMPOSITION
[PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO]
LY-ALPHA
MECHANICAL FEEDBACK
Astrophysics::Galaxy Astrophysics
INTERSTELLAR-MEDIUM
starburst [galaxies]
ISM [infrared]
numerical [methods]
Astronomy and Astrophysics
Astrophysics - Astrophysics of Galaxies
STARBURST GALAXY
[PHYS.ASTR.GA]Physics [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA]
Physics and Astronomy
radiative transfer
Space and Planetary Science
Astrophysics of Galaxies (astro-ph.GA)
LARGE-MAGELLANIC-CLOUD
structure [ISM]
X-RAY BINARIES
Zdroj: ASTRONOMY & ASTROPHYSICS
Astronomy and Astrophysics-A&A
Astronomy and Astrophysics-A&A, 2022, ⟨10.1051/0004-6361/202243866⟩
ISSN: 0004-6361
1432-0746
Popis: (abridged) Quantifying the ISM porosity to ionizing photons in nearby galaxies may improve our understanding of the mechanisms leading to Lyman Continuum photons leakage from galaxies. Primitive galaxies with low metal and dust content have been shown to host a more patchy and porous ISM than their high-metallicity counterparts. To what extent this peculiar structure contributes to the leakage of ionizing photons remains to be quantitatively studied. To address these questions we build a refined grid of models including density-bounded regions and a possible contribution of an X-ray source. Using MULTIGRIS, a new Bayesian code based on Monte Carlo sampling, we combine the models as sectors under various assumptions to extract the probability density distributions of the parameters and infer the corresponding escape fractions from H II regions (fesc,HII). We apply this new code to a sample of 39 well-know local starbursting dwarf galaxies from the Dwarf Galaxy Survey. We confirm previous results hinting at an increased porosity to ionizing photons of the ISM in low-metallicity galaxies and provide, for the first time, quantitative predictions for fesc,HII. The predicted fesc,HII for low-metallicity objects span a large range of values, up to 60%, while the values derived for more metal-rich galaxies are globally lower. We also examine the influence of other parameters on the escape fractions, and find that the specific star-formation rate correlates best with fesc,HII . Finally, we provide observational line ratios which could be used as tracers of the photons escaping from density-bounded regions. Although this multi-sector modelling remains too simple to fully capture the ISM complexity, it can be used to preselect galaxy samples with potential leakage of ionizing photons based on current and up-coming spectral data in unresolved surveys of local and high-redshift galaxies.
39 pages, 24 figures, accepted for publication in A&A
Databáze: OpenAIRE
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