Quantifying Distributions of Lyman Continuum Escape Fraction

Abstract

Simulations have indicated that most of the escaped Lyman continuum photons escape through a minority of solid angles with near complete transparency, with the remaining majority of the solid angles largely opaque, resulting in a very broad and skewed probability distribution function (PDF) of the escape fraction when viewed at different angles. Thus, the escape fraction of Lyman continuum photons of a galaxy observed along a line of sight merely represents the properties of the interstellar medium along that line of sight, which may be an ill-representation of true escape fraction of the galaxy averaged over its full sky. Here we study how Lyman continuum photons escape from galaxies at $z=4-6$, utilizing high-resolution large-scale cosmological radiation-hydrodynamic simulations. We compute the PDF of the mean escape fraction ($⟨f_{\mathrm{esc},1D}⟩$) averaged over mock observational samples, as a function of the sample size, compared to the true mean (had you an infinite sample size). We find that, when the sample size is small, the apparent mean skews to the low end. For example, for a true mean of 6.7%, an observational sample of (2,10,50) galaxies at $z=4$ would have have 2.5% probability of obtaining the sample mean lower than $⟨f_{\mathrm{esc},1D}⟩=$(0.007%, 1.8%, 4.1%) and 2.5% probability of obtaining the sample mean being greater than (43%, 18%, 11%). Our simulations suggest that at least $\sim$ 100 galaxies should be stacked in order to constrain the true escape fraction within 20% uncertainty.

arXiv commentAccepted to the ApJ Letters, 12 pages, 4 figures

References in corpus (26)

• Seven-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• Starburst99: Synthesis Models for Galaxies with Active Star Formation
• Cosmological Hydrodynamics with Adaptive Mesh Refinement: a new high resolution code called RAMSES
• Dust Masses, PAH Abundances, and Starlight Intensities in the SINGS Galaxy Sample
• Multi-scale initial conditions for cosmological simulations
• Cosmological Reionization by Stellar Sources
• Escape fraction of ionizing photons during reionization: effects due to supernova feedback and runaway OB stars
• Metallicity Effects on Dust Properties in Starbursting Galaxies
• RAMSES-RT: Radiation hydrodynamics in the cosmological context
• The Direct Detection of Lyman-Continuum Emission from Star-forming Galaxies at z~3
• The Universe Was Reionized Twice
• Turbulent Structure of a Stratified Supernova-Driven Interstellar Medium
• Ionizing Photon Escape Fractions from High Redshift Dwarf Galaxies
• Dust-to-gas Ratio and Metal Abundance in Dwarf Galaxies
• Building Merger Trees from Cosmological N-body Simulations
• Evolution of the Intergalactic Opacity: Implications for the Ionizing Background, Cosmic Star Formation, and Quasar Activity
• Detections of Lyman Continuum from Star-forming Galaxies at z~3 Through Subaru/Suprime-Cam Narrow-band Imaging
• Probing the Dust Properties of Galaxies at Submillimetre Wavelengths II. Dust-to-gas mass ratio trends with metallicity and the submm excess in dwarf galaxies
• A Refined Estimate of the Ionizing Emissivity from Galaxies at z~3: Spectroscopic Follow-up in the SSA22a Field
• Narrowband imaging of Escaping Lyman-Continuum Emission in the SSA22 Field
• Ionizing radiation from z=4-10 galaxies
• A Monte Carlo simulation of the intergalactic absorption and the detectability of the Lyman continuum from distant galaxies
• Narrowband Lyman-Continuum Imaging of Galaxies at z ~ 2.85
• Escape of Lyman-alpha and continuum photons from star-forming galaxies
• On the Evolution of the Cosmic Ionizing Background
• Lyman continuum galaxies and the escape fraction of Lyman break galaxies

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• Stellar Population Effects on the Inferred Photon Density at Reionization
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• Hubble imaging of the ionizing radiation from a star-forming galaxy at z=3.2 with fesc>50%
• An extreme [OIII] emitter at $z=3.2$: a low metallicity Lyman continuum source
• Feedback-regulated star formation and escape of LyC photons from mini-haloes during reionisation
• The Low-Redshift Lyman Continuum Survey II: New Insights into LyC Diagnostics
• The production and escape of Lyman-Continuum radiation from star-forming galaxies at z~2 and their redshift evolution
• The redshift evolution of escape fraction of hydrogen ionizing photons from galaxies
• New Insights on Ly-alpha and Lyman Continuum Radiative Transfer in the Greenest Peas
• Ionising the Intergalactic Medium by Star Clusters: The first empirical evidence
• The Lyman Continuum escape fraction of galaxies at z=3.3 in the VUDS-LBC/COSMOS field
• The JWST-PRIMAL Legacy Survey. A JWST/NIRSpec reference sample for the physical properties and Lyman-$\alpha$ absorption and emission of $\sim 500$ galaxies at $z=5.5-13.4$
• A VLT/FORS2 view at $z\sim 6$: Lyman-$\alpha$ emitter fraction and galaxy physical properties at the edge of the epoch of cosmic reionization
• The THESAN project: ionizing escape fractions of reionization-era galaxies
• The Lyman Continuum Escape Fraction of Low-Mass Star-Forming Galaxies at z~1
• Revisiting the Lyman Continuum Escape Crisis: Predictions for z > 6 from Local Galaxies
• A Low Lyman Continuum Escape Fraction of $<10\%$ for Extreme [OIII] Emitters in an Overdensity at z$\sim 3.5$
• The spectral evolution of the first Galaxies. III. Simulated James Webb Space Telescope spectra of reionization-epoch galaxies with Lyman continuum leakage
• Three Lyman-alpha emitting galaxies within a quasar proximity zone at z=5.8
• Intergalactic Lyman continuum photon budget in the past 5 billion years
• Constraints on the Lyman continuum escape fraction for faint star forming galaxies
• UV absorption lines and their potential for tracing the Lyman continuum escape fraction
• The VANDELS survey: a measurement of the average Lyman-continuum escape fraction of star-forming galaxies at z=3.5
• Limits on the LyC signal from z~3 sources with secure redshift and HST coverage in the E-CDFS field
• The Low-redshift Lyman-continuum Survey: [S II]-deficiency and the leakage of ionizing radiation
• New Methods for Identifying Lyman Continuum Leakers and Reionization-Epoch Analogues
• Neutral Gas Properties and Ly$\alpha$ Escape in Extreme Green Pea Galaxies
• The HDUV Survey: Six Lyman Continuum Emitter Candidates at z~2 Revealed by HST UV Imaging
• MgII in the JWST Era: a Probe of Lyman Continuum Escape?
• Predicting LyC emission of galaxies using their physical and Ly$\alpha$ emission properties
• Lyman Continuum Escape Fraction in Ly$\alpha$ Emitters at $z\simeq 3.1$
• Two Modes of LyC Escape From Bursty Star Formation: Implications for [C II] Deficits and the Sources of Reionization
• Physics of Prodigious Lyman Continuum Leakers
• On the origin of low escape fractions of ionizing radiation from massive star-forming galaxies at high redshift
• Lyman Continuum Escape Fraction from Low-mass Starbursts at z=1.3
• The importance of stochasticity in determining galaxy emissivities and UV LFs during cosmic dawn and reionization
• Linking Mg II and [O II] spatial distribution to ionizing photon escape in confirmed LyC leakers and non-leakers
• Lyman continuum leaker candidates among highly ionised, low-redshift dwarf galaxies selected from HeII
• Identifying reionization-epoch galaxies with extreme levels of Lyman continuum leakage in James Webb Space Telescope surveys
• The Lyman-alpha and Continuum Origins Survey. I. Survey description and Ly$\alpha$ imaging
• Candidate z ~ 2.5 Lyman Continuum Sources in the GOODS Fields
• Inferring the Distribution of the Ionising Photon Escape Fraction
• SDSS-IV MaNGA: an observational evidence of density bounded region in a Lyman-$\alpha$ emitter
• Constraint on Matter Power Spectrum on $10^6-10^9{M}_{\odot }$ Scales from ${\tau }_e$
• Impact of anisotropic photon emission from sources during the epoch of reionisation
• Lyman continuum observations across cosmic time: recent developments, future requirements