Characterize burstiness below the low-mass galaxy completeness limit

Characterize the distribution and prevalence of bursty star formation in galaxies with stellar masses below approximately 10^8–10^8.5 solar masses at high redshift.

Background

The paper models U13151-like episodes as short-lived, intense phases of star formation in low-mass galaxies and uses their duty cycle to estimate their possible contribution to the escaping ionizing emissivity. However, existing high-redshift samples are incomplete at stellar masses below approximately 108–108.5 solar masses.

Consequently, the frequency and distribution of bursty phases in the ultra-low-mass population remain insufficiently established, limiting the reliability of extrapolations about their role during reionization.

References

We caution, however, that most of the current studies are not complete at $\log_{10}(M_{\bigstar}/M_{\odot})\lesssim8\text{--}8.5$ at any given time, and the behavior of the burstiness distribution below these $M_{\bigstar}$ remains still poorly constrained.

— 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”