Constrain the Lyman-continuum escape fraction of U13151

Constrain the Lyman-continuum escape fraction of U13151 to determine the contribution of U13151-like phases to the escaping ionizing-photon emissivity of low-mass galaxies.

Background

The inferred contribution of U13151-like episodes to the escaping ionizing-photon budget depends strongly on the assumed Lyman-continuum escape fraction. The paper estimates the escape fraction indirectly from the ultraviolet slope, but the resulting uncertainty is large, and different plausible values produce substantially different contributions.

A direct or substantially improved constraint on the escape fraction is therefore needed to assess whether short-lived U13151-like bursts make a minor or major contribution to the ionizing output of the low-mass galaxy population.

References

Since $f_{\rm esc}$ for U13151 is not well constrained ($f_{\rm esc}=19\pm17\%$ using the relation from \citealt{chisholm_far-ultraviolet_2022}), we repeat the calculation assuming $f_{\rm esc}=1\%$, $5\%$, $10\%$, $15\%$, and $20\%$ for U13151-like systems.

— PRISMS/U13151. A Glimpse into the Earliest Phases of Galaxy Formation through an Ultra-Faint System $\approx$ 500 Myr after the Big Bang  (2610.26560 - Rinaldi et al., 19 Oct 2026) in Section 4.3, “The role of U13151-like systems during Cosmic Reionization”