The star-forming and ionizing properties of dwarf z ~ 6–9 galaxies in JADES: insights on bursty star formation and ionized bubble growth

ABSTRACT Reionization is thought to be driven by faint star-forming galaxies, but characterizing this population has long remained very challenging. Here, we utilize deep nine-band JADES (JWST Advanced Deep Extragalactic Survey)/NIRCam (Near-Infrared Camera) imaging to study the star-forming and ionizing properties of 756 $z\sim 6-9$ galaxies, including hundreds of very ultraviolet (UV)-faint objects ($M_\mathrm{UV}\gt -18$). The faintest ($m\sim 30$) galaxies in our sample typically have stellar masses of $M_\ast \sim (1-3)\times 10^7\ \mathrm{ M}_\odot$ and young light-weighted ages ($\sim$50 Myr), though some show strong Balmer breaks implying much older ages ($\sim$500 Myr). We find no evidence for…

• NS
  National Science Foundation

  Awards: DGE-2137419, AST-1828315, AST-2109066
• UO
  University of Arizona

  Award: NAS5-02015
• SA
  Science and Technology Facilities Council

  Awards: ST/M001172/1, ST/W001438/1, ST/V000918/1, ST/V00087X/1, ST/S004831/1, ST/S004831/1, ST/W001438/1
• HE
  H2020 European Research Council

  Awards: 101040227, 789056, 2742605, 695671