The Escape Fraction of Ionizing Photons During the Epoch of Reionization: observability with the Square Kilometre Array

Abstract

One of the most important parameters in characterizing the Epoch of Reionization, the escape fraction of ionizing photons, $f_{\mathrm{esc}}$, remains unconstrained both observationally and theoretically. With recent work highlighting the impact of galaxy-scale feedback on the instantaneous value of $f_{\mathrm{esc}}$, it is important to develop a model in which reionization is self-consistently coupled to galaxy evolution. In this work, we present such a model and explore how physically motivated functional forms of $f_{\mathrm{esc}}$ affect the evolution of ionized hydrogen within the intergalactic medium. Using the $21$cm power spectrum evolution, we investigate the likelihood of observationally distinguishing between a constant $f_{\mathrm{esc}}$ and other models that depend upon different forms of galaxy feedback. We find that changing the underlying connection between $f_{\mathrm{esc}}$ and galaxy feedback drastically alters the large-scale $21$cm power. The upcoming Square Kilometre Array Low Frequency instrument possesses the sensitivity to differentiate between our models at a fixed optical depth, requiring only $200$ hours of integration time focused on redshifts $z=7.5-8.5$. Generalizing these results to account for a varying optical depth will require multiple $800$ hour observations spanning redshifts $z=7-10$. This presents an exciting opportunity to observationally constrain one of the most elusive parameters during the Epoch of Reionization.

14 pages, 8 figures, 2 tables

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Cited by in corpus (14)

• Introducing the THESAN project: radiation-magnetohydrodynamic simulations of the epoch of reionization
• The THESAN project: properties of the intergalactic medium and its connection to Reionization-era galaxies
• Astraeus I: The interplay between galaxy formation and reionization
• Semi-analytic forecasts for JWST -- IV. Implications for cosmic reionization and LyC escape fraction
• The origin of dust in galaxies across cosmic time
• AstraeusIV : Quantifying the star formation histories of galaxies in the Epoch of Reionization
• Astraeus VIII: A new framework for Lyman-$\alpha$ emitters applied to different reionisation scenarios
• Astraeus III: The environment and physical properties of reionization sources
• Deep-Learning Study of the 21cm Differential Brightness Temperature During the Epoch of Reionization
• Mapping reionization bubbles in the JWST era I: empirical edge detection with Lyman alpha emission from galaxies
• Thermal and Reionisation History within a Large-Volume Semi-Analytic Galaxy Formation Simulation
• Constraining cosmic reionization by combining the kinetic Sunyaev-Zel'dovich and the 21 cm power spectra
• Reconstructing the epoch of reionisation with Planck PR4
• Fisher matrix forecasts on the astrophysics of galaxies during the epoch of reionisation from the 21-cm power spectra