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Abstract The bursty, time-variable nature of star formation in the first billion years, as revealed by JWST, drives phases of temporary quiescence in low-mass galaxies that quench after starbursts. These galaxies provide unique probes of the burstiness of early star formation and its underlying physical processes. Using the serra cosmological zoom-in simulations, we analyze over 200 galaxies with M ⋆ −17. By forward modeling their spectral energy distributions, we show that they are faint (〈 M UV 〉 = −15.6 for M ⋆ = 10 8 M ⊙ ), have strong Balmer breaks (>0.5), and no emission lines. Comparing our predicted fractions with JWST results, we find similar luminosity-dependent trends; however, the observed fractions of temporarily quiescent galaxies at M UV ∼ −20 to −19 are higher, suggesting that stronger feedback or additional mechanisms beyond supernovae may be at play. We propose searching for F200W dropouts and satellites in the proximity (10 10 M ⊙ ) galaxies as effective strategies to uncover the hidden majority of faint ( M UV > −17), temporarily quiescent systems, crucial for constraining early feedback processes in low-mass galaxies.
Gelli et al. (Mon,) studied this question.